keystone-manage2 does not list granted roles

RCB has complained that the revised keystone-manage implementation does not provide a "list" or "show" complement to the "grant_role" and "revoke_role" commands (e.g. "list_granted_roles" or "list_role_grants").

This was an oversight in the implementation which breaks usability, as the only way to check from the CLI if a role has been granted to a user is to 1) attempt to grant it, 2) check for failure (IntegrityError), and 3) immediately revoke it you did not desire to actually grant it... not a pretty pattern.