Unconditionally add AuthTransport.
Unconditionally add AuthTransport.

Today, endpoints implementing v2 cannot properly fallback to v1 because the underlying transport that deals with authentication (Basic / Token) doesn't get annotated.

This doesn't affect DockerHub because the DockerHub endpoint appears as 'https://index.docker.io/v1/' (in .dockercfg), and the 'v1' tricks this logic just long enough that the transport is always annotated for DockerHub accesses.

Signed-off-by: Matt Moore <866b498749d560dfd4b9805e44d1fa0b8bc948c7@google.com>

AdamOssenford/docker-pi,AdamOssenford/docker-pi,AdamOssenford/docker-pi