update Travis config to reflect that PyYAML 5.x is no longer compatible with Python 2.6

[boegel]

No description provided.

[boegelbot]

Travis test report: 1/8 runs failed - see https://travis-ci.org/easybuilders/easybuild-framework/builds/506493325

Only showing partial log for 1st failed test suite run 2889.8;
full log at https://travis-ci.org/easybuilders/easybuild-framework/jobs/506493333

...
ConstructorError: could not determine a constructor for the tag '!join'
  in "<string>", line 5, column 6:
    fb1: !join [foo, bar]
         ^

======================================================================
ERROR: test_parse_yeb (test.framework.yeb.YebTest)
Test parsing of .yeb easyconfigs.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/test/framework/yeb.py", line 97, in test_parse_yeb
    ec_yeb = EasyConfig(os.path.join(test_yeb_easyconfigs, '%s.yeb' % filename))
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/easyconfig.py", line 343, in __init__
    auto_convert_value_types=auto_convert_value_types)
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/parser.py", line 105, in __init__
    self._set_formatter(filename)
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/parser.py", line 196, in _set_formatter
    self._formatter.parse(self.rawcontent)
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/format/yeb.py", line 96, in parse
    self.parsed_yeb = yaml.load(txt)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/__init__.py", line 114, in load
    return loader.get_single_data()
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 45, in get_single_data
    return self.construct_document(node)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 54, in construct_document
    for dummy in generator:
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 399, in construct_yaml_seq
    data.extend(self.construct_sequence(node))
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 124, in construct_sequence
    for child in node.value]
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 94, in construct_object
    data = constructor(self, node)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 420, in construct_undefined
    node.start_mark)
ConstructorError: could not determine a constructor for the tag '!join'
  in "<string>", line 69, column 7:
        - &blas !join [*blaslib, -, *blasver]
          ^

----------------------------------------------------------------------
Ran 598 tests in 648.300s

FAILED (errors=2)
ERROR: Not all tests were successful.
Log available at /tmp/eb-af3wOY/eb-7NmA97/easybuild-tests-G2a_1A.log
travis_time:end:0bbcecf0:start=1552599404489418484,finish=1552600053528664724,duration=649039246240
�[0K�[32;1mThe command "python -O -m test.framework.suite 2>&1 | tee test_framework_suite.log" exited with 0.�[0m

travis_time:start:19dfd680
�[0K$ IGNORE_PATTERNS="vsc\.install\.shared_setup|no GitHub token available|skipping SvnRepository test|lib/python2.6/site-packages|required Lmod as modules tool"
travis_time:end:19dfd680:start=1552600053535112768,finish=1552600053538194689,duration=3081921
�[0K�[32;1mThe command "IGNORE_PATTERNS="vsc\.install\.shared_setup|no GitHub token available|skipping SvnRepository test|lib/python2.6/site-packages|required Lmod as modules tool"" exited with 0.�[0m

travis_time:start:0584f3db
�[0K$ PRINTED_MSG=$(egrep -v "${IGNORE_PATTERNS}" test_framework_suite.log | grep '\.\n*[A-Za-z]' || true)
travis_time:end:0584f3db:start=1552600053543801683,finish=1552600053552793412,duration=8991729
�[0K�[32;1mThe command "PRINTED_MSG=$(egrep -v "${IGNORE_PATTERNS}" test_framework_suite.log | grep '\.
*[A-Za-z]' || true)" exited with 0.�[0m

travis_time:start:278ef9c8
�[0K$ test "x$PRINTED_MSG" = "x" || (echo "Found printed messages in output of test suite\n${PRINTED_MSG}" && exit 1)
Found printed messages in output of test suite\n........................./tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/format/yeb.py:96: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
  self.parsed_yeb = yaml.load(txt)
.................................................................................................................................................................................................../tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/test/framework/yeb.py:145: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
  loaded = yaml.load('\n'.join(stream))
ERROR: test_join (test.framework.yeb.YebTest)
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/test/framework/yeb.py", line 145, in test_join
    loaded = yaml.load('\n'.join(stream))
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/__init__.py", line 114, in load
    return loader.get_single_data()
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 45, in get_single_data
    return self.construct_document(node)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 54, in construct_document
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 404, in construct_yaml_map
    value = self.construct_mapping(node)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 214, in construct_mapping
    return BaseConstructor.construct_mapping(self, node, deep=deep)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 139, in construct_mapping
    value = self.construct_object(value_node, deep=deep)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 94, in construct_object
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 420, in construct_undefined
    node.start_mark)
ERROR: test_parse_yeb (test.framework.yeb.YebTest)
Test parsing of .yeb easyconfigs.
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/test/framework/yeb.py", line 97, in test_parse_yeb
    ec_yeb = EasyConfig(os.path.join(test_yeb_easyconfigs, '%s.yeb' % filename))
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/easyconfig.py", line 343, in __init__
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/parser.py", line 105, in __init__
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/parser.py", line 196, in _set_formatter
    self._formatter.parse(self.rawcontent)
  File "/tmp/506493333/lib/python2.7/site-packages/easybuild_framework-3.9.0.dev0-py2.7.egg/easybuild/framework/easyconfig/format/yeb.py", line 96, in parse
    self.parsed_yeb = yaml.load(txt)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/__init__.py", line 114, in load
    return loader.get_single_data()
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 45, in get_single_data
    return self.construct_document(node)
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 54, in construct_document
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 399, in construct_yaml_seq
    data.extend(self.construct_sequence(node))
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 124, in construct_sequence
    for child in node.value]
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 94, in construct_object
  File "/home/travis/virtualenv/python2.7.14/lib/python2.7/site-packages/yaml/constructor.py", line 420, in construct_undefined
    node.start_mark)
Log available at /tmp/eb-af3wOY/eb-7NmA97/easybuild-tests-G2a_1A.log

*bleep, bloop, I'm just a bot (boegelbot v20180813.01)*Please talk to my owner @boegel if you notice you me acting stupid),or submit a pull request to https://github.com/boegel/boegelbot fix the problem.

[migueldiascosta]

lgtm

[migueldiascosta]

Going in, thanks @boegel!