We really should only have code that create endpoints once, making all
osc calls get_or_set adds 3 seconds per call for no really good
reason.
This also stops creating the internal endpoints in the service
catalog. It's a pattern that we're trying not to propogate, so lets
not have it in devstack any more.
Change-Id: Ia8cefe43753900d62117beae330db46deb6a9fc9