Fix version discovery and auth_plugins

V3Client support added version discovery and session supports. Most
of the external auth system doesn't support this. This fix bypasses
version discovery if the idenity service doesn't support that. Session
is used only if  no external auth plugin is used

Change-Id: Ia84a2ad45940d35c5ef740727f5f7477c72ea9d4
Closes-Bug: #1333961