resourcepolicyplugin: Emit resources released signal for acquiring resources as well.

Change-Id: Ic1b31b1c4dd91251eec278a0840bb06635c828c6
Done-with: Juho Hämäläinen <juho.hamalainen@tieto.com>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>