Make tox.ini run pep8 checks on bin.
Make tox.ini run pep8 checks on bin.

This updates the pep8 checks in our tox.ini file so that we are
also scanning the bin directory.

Change-Id: Ia3465a4bbc6a5fef7da4de45b736d8950c920963

gkotton/vmware-nsx,gkotton/vmware-nsx