As discussed in API review, this field exists for convenience right
now. Since the username/groups are encoded in the Credential sent in
the LoginRequestStatus, the client still has access to their
user/groups information. We want to remove this for now to be
conservative and limit our API surface area (smaller surface area =
less to maintain). We can always add this back in the future.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>