Clean up a little cruft

OpenStack runs a git service now, so instead of linking to github URLs,
link to git.openstack.org.
Versions for pbr in setup.py actually wind up being an error (and a very
odd one) Remove them.
The setup hook in setup.cfg is no longer needed.

Change-Id: I8f48ac194e6c01e9bb06fa5df6f2b2bf28c01636
Merge "Clean up a little cruft"