Fixes bug 1064008
The motivation for switching over to the public API:
- the registry API is more of an artifact of the internal glance
architecture than a true public API
- the registry API exposes internal attributes such as the backend
store image location, which is stripped from the API-provided image
representation for security reasons (hence should not bleed into
metering)
- the internalURL should be available from the keystone service catalog,
so we can get rid of the registry host/port config
Change-Id: I0d75392066a020c608a67f1ecf0e8dba15aa48f0