Ensure no Python modules under astropy/utils/compat are excluded from the source distribution
Added a changelog mention of this, though it won't be of interest to most users (packagers maybe though)
Merge pull request #2854 from embray/issue-2854

Astropy 0.4.1 on pypi is broken for python 2.6 due to missing _odict_py2 _fractions_py2 directories