Commands that do not reuire authentication still call things that want
to check the service catalog; no auth means no service catalog.
(I'm looking at you OSC's is_networking_enabled()) Get more aggressive
at not doing auth when it is not required.
The cost of this is commands with auth_required=False need to be more
selective about what they do with ClientManager.auth_ref as it will
now happily return None when auth is not required _and_ no credentials
are present, rather than throw up all over the place.
Change-Id: I72ae6154268bdf26be6054c0fef6a4c67c71119c