Fix issue on shutdown.

Fix issue on shutdown.

On shutdown, former behaviour was deleting ccap and qos from the operational datastore directly.
But at no point those were initialized. So if no action was perfomed by the user, we could see the attached log.

I think all we need is the close the ListenerRegistration and eveything will be deleted on the operational datastore.

associated logs: https://gist.github.com/23396b108c1742b9299b

Change-Id: I1816387787deb7e441a55df3dd58c9ccaf892d4e
Signed-off-by: Alexis de Talhouët <adetalhouet@inocybe.com>