Sync requirements with openstack/requirements

This switches us from the ipaddr lib, to the netaddr lib which is
in use by other openstack projects.

This also means an updated:

- keystoneclient
- hacking
- distribute
- setuptools

Finally, we're violating two new Hacking rules (H231 / H501), so
we cleanup these violations.

Change-Id: I6658a0209fc7f0942188f7c518171e6b1fa2b4aa