API Remove results.expectGcu setting - not needed

The setting is no longer needed, after some local testing that
demonstrates that, in the presence of files without group constant
data, the ResultsReader still stores data without error. A warning
message is printed indicating the setting is no longer
needed.

docs/defaultSettings.rst

@@ -128,19 +128,6 @@ If true, store the micro-group cross sections.
   Type: bool
   
 
-.. _results-expectGcu:
-
----------------------
-``results.expectGcu``
----------------------
-
-Set this to False if no homogenized group contants are present in the output, as if ``set gcu -1`` is preset in the input file
-::
-
-  Default: True
-  Type: bool
-  
-
 .. _sampler-allExist:
 
 --------------------

serpentTools/parsers/results.py

@@ -374,10 +374,6 @@ def _inspectData(self):
                 .format(self.filePath, self._numUniv,
                         self._counter['rslt'], self._counter['meta']))
         if not self.resdata and not self.metadata:
-            if not self.settings['expectGcu']:
-                raise SerpentToolsException(
-                    "Metadata and results data were not found in {}"
-                    .format(self.filePath))
             for keys, dictUniv in iteritems(self.universes):
                 if dictUniv.hasData():
                     return

serpentTools/settings.py

@@ -1,5 +1,6 @@
 """Settings to yield control to the user."""
 import os
+from warnings import warn
 
 from six import iteritems
 from yaml import safe_load
@@ -26,6 +27,8 @@
 
 """
 
+_DEPRECATED = {'results.expectGcu'}
+
 SETTING_OPTIONS_FMTR = "Options: [{}]"
 defaultSettings = {
     'branching.intVariables': {
@@ -70,13 +73,6 @@
                        'detectors',
         'type': list
     },
-    'results.expectGcu': {
-        'default': True,
-        'description': 'Set this to False if no homogenized group contants '
-                       'are present in the output, as if ``set gcu -1`` is '
-                       'preset in the input file',
-        'type': bool,
-    },
     'verbosity': {
         'default': 'warning',
         'options': messages.LOG_OPTS,
@@ -305,12 +301,15 @@ def setValue(self, name, value):
             If the value is not of the correct type
 
         """
-        if self.__inside:
-            self.__originals[name] = self[name]
+        if name in _DEPRECATED:
+            warn("Setting {} has been removed.".format(name))
+            return
         if name not in self:
             raise KeyError('Setting {} does not exist'.format(name))
         self._defaultLoader[name].validate(value)
         # if we've made it here, then the value is valid
+        if self.__inside:
+            self.__originals[name] = self[name]
         if self._defaultLoader[name].updater is not None:
             value = self._defaultLoader[name].updater(value)
         dict.__setitem__(self, name, value)