rbd: include image id within service daemon registration
rbd: include image id within service daemon registration

This is needed to allow an in-memory lookup of librbd performance
metrics on the Ceph dashboard without the need to query the Ceph
cluster or iterate through all available metrics.

Signed-off-by: Jason Dillaman <ae60fc3de6a668216bf89c7b1e7bff85becaa6b2@redhat.com>

open-iscsi/tcmu-runner,agrover/tcmu-runner,open-iscsi/tcmu-runner