The existing version discovery process is awesome, but in the normal flows it
ultimately returns urls, not the full endpoint data, so it's not
possible to know what version was discovered.
Make an EndpointData object that gets created and plumb that through the
stack so that it's possible to request EndpointData instead of just
endpoints. The existing discovery logic is unchanged, and the existing
methods continue to return the data they returned before.
Change-Id: Id48861e7d6d20be16f61cb375a21bca4a43a2500
337e5af637