Updated openstack/openstack
Project: openstack/keystone  d9d1ce76124f0b755a5ccfca01b814f4ff8aee57

improve dependency injection doc strings

This also renames the provider_name argument to better convey it's
status as a kwarg for internal use only.

Change-Id: Ie1afee4e37cfa149ddb73a001985c98aa90b97a5