Storage services need keystoneclient not keystone

The service recipes have been pulling in the entire
python-keystone package, which is the entire Keystone
set of services. This hasn't been necessary since
some time after Grizzly, when the tokenauth middleware
was moved to the client.

Change-Id: I6d326352ab5c8079cc5c405161475ec0354c5593
Related-Bug: #1305318