In this new code:

                    mod_file = os.path.abspath(getattr(module, '__file__', full_path))
                    realpath = os.path.splitext(os.path.realpath(mod_file))[0]
                    fullpath_noext = os.path.splitext(os.path.realpath(full_path))[0]

we get

modfile == /usr/lib/python2.7/dist-packages/lazr/restfulclient/tests/test_error.pyc
realpath == /usr/lib/python2.7/dist-packages/lazr/restfulclient/tests/test_error
fullpath_noext == /usr/share/pyshared/lazr/restfulclient/tests/test_error

for this file:

lrwxrwxrwx 1 root root 71 Mai 26  2013 /usr/lib/python2.7/dist-packages/lazr/restfulclient/tests/test_error.py -> ../../../../../../share/pyshared/lazr/restfulclient/tests/test_error.py

Which is as expected in Debian/Ubuntu as the *.pyc file is a real file in /usr/lib/python2.7, but the *.py is symlinked to /usr/share/.

This new patch essentially enforces that the *.py file is not a symlink, which breaks the Debian-ish way of installing python 2 modules.