This was a very small update, I'm hoping to rebase after this to solve some

This was a very small update, I'm hoping to rebase after this to solve some
other problems. I started looking at the tests in this update. This update I
spent fixing the tests to work with my new code.

--\ mediagoblin/db/migration_tools.py
--| Merging from ticket 679

--\ mediagoblin/db/migrations.py
--| Added unique constraint to Privilege.privilege_name

--\ mediagoblin/db/models.py
--| Deleted vestigial Privilege.is_admin_or_moderator method

--\ mediagoblin/templates/mediagoblin/moderation/user.html
--| Add a `Ban User` / `UnBan User` for admin

--\ mediagoblin/test/test_api.py
--| Fixed test with my new changes

--\ mediagoblin/test/test_auth.py
--| Try to fix test, still having problems

--\ mediagoblin/test/test_modelmethods.py
--| Wrote my first test for the User.has_privilege method

--\ mediagoblin/test/test_modelmethods.py
--| Fixed test with my new changes

--\ mediagoblin/test/test_sqlmigrations.py
--| Merging from ticket 679

--\ mediagoblin/test/tools.py
--| Editted add_fixture_user to allow for privileges rather than active column