[registry] Renew OpenStack connection on an Unauthorized error [#fixes 50935167]

If we get an Unauthorized error, it could mean that the OpenStack auth token has expired, so we are
going renew the fog connection one time to make sure that we get a new non-expired token.
Merge pull request #235 from cloudfoundry/openstack_registry

[registry] Renew OpenStack connection on an Unauthorized error [#fixes 50935167]