The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.
Fix problems found.
Remove hacking and friends from lower-constraints, they are not needed
for installation.
Change-Id: I7dd7a16d2b2d75120fa14de1d5c080a1a1c9729d
* Ported over from the Catalyst repos into its own
plugin for better maintainability and ease of sharing
with upstream.
Change-Id: I4e7e1787330d549c59ede6f024e1216f5a073ecd