CA-276601: cleanup refcounts when deleting unused volume
CA-276601: cleanup refcounts when deleting unused volume

Signed-off-by: Mark Syms <655512b2a8f1aba6e4085462b623575da824f038@citrix.com>
Reviewed-by: Chandrika Srinivasan <51ae5eeda27fe08017d2d63c87755f0707891830@citrix.com>

chandrikas/sm,xapi-project/sm,chandrikas/sm,xapi-project/sm,xapi-project/sm,chandrikas/sm