Make auth_token return a V2 Catalog

As there is no way to distinguish a v2 or v3 catalog from the headers
provided to an application we will for the meantime always return a v2
catalog. This should not cause any issues as the full token data is not
provided to the service so there is no-one that will get caught out by a
v2/v3 mix, and anyone that is already supporting the v3 catalog format
will have to support the v2 catalog format as well so it will continue
to work.

Change-Id: Ic9b38e0ba4682b47ae295bd3f89bac59ef7437cf
Closes-Bug: #1302970
Merge "Make auth_token return a V2 Catalog"