Comment 4 for bug 1180033

As long as we're compatible with openstack-wide requirements [1], we should support the latest dependencies we can. Requirements are generally pinned when upgrading causes issues for the project, however I'm not clear on the history of why these particular requirements are pinned as such. I'm happy to see them unpinned, if possible.

[1]: https://github.com/openstack/requirements/blob/master/tools/pip-requires