* Update module_utils.six to latest
We've been held back on the version of six we could use on the module
side to 1.4.x because of python-2.4 compatibility. Now that our minimum
is Python-2.6, we can update to the latest version of six in
module_utils and get rid of the second copy in lib/ansible/compat.
* Unittests for some of module_common.py
* Port test_run_command to use pytest-mock
The use of addCleanup(patch.stopall) from the unittest idiom was
conflicting with the pytest-mock idiom of closing all patches
automatically. Switching to pytest-mock ensures that the patches are
closed and removing the stopall stops the conflict.