Whilst historically we always wanted keystoneauth to do the most
permissive thing and allow a versioned or unversioned entry in a service
catalog there are now cases where we would prefer to fail when the
catalog is misconfigured. This will allow a client to opt out of
versioned catalog endpoints to insist that the deployment is correctly
configured.
Closes-Bug: #1668484
Change-Id: Ided0e0c7409994f703175fe61bd4043b840bcf1e
3ce5cb4bf6