Update Rackspace group

Change-Id: I0a629421cfa4270357b3bb328e30bec4e33abd9a
Reviewed-on: https://review.openstack.org/31205
Reviewed-by: Sean Dague <sean@dague.net>
Approved: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Tested-by: Jenkins