Revert "This time, use test-requirements."

This reverts commit 74a0507.

https://travis-ci.org/gitpython-developers/GitPython/jobs/561334516#L634

.travis.yml

@@ -22,7 +22,6 @@ install:
   - python --version; git --version
   - git submodule update --init --recursive
   - git fetch --tags
-  - pip install -r requirements.txt
   - pip install -r test-requirements.txt
   - pip install codecov sphinx
 

git/compat.py

@@ -30,10 +30,7 @@
 is_win = (os.name == 'nt')
 is_posix = (os.name == 'posix')
 is_darwin = (os.name == 'darwin')
-if hasattr(sys, 'getfilesystemencoding'):
-    defenc = sys.getfilesystemencoding()
-if defenc is None:
-    defenc = sys.getdefaultencoding()
+defenc = sys.getdefaultencoding()
 
 if PY3:
     import io

git/repo/base.py

@@ -4,7 +4,6 @@
 # This module is part of GitPython and is released under
 # the BSD License: http://www.opensource.org/licenses/bsd-license.php
 
-from builtins import str
 from collections import namedtuple
 import logging
 import os

requirements.txt

@@ -1,4 +1 @@
 gitdb2 (>=2.0.0)
-gitdb>=0.6.4
-ddt>=1.1.1
-future>=0.9