Bug 1386: Avoid commit deadlock

Changed the executor in DOMDataCommitCoordinatorImpl to a new
class DeadlockDetectingListeningExecutorService added to yangtools util.
This detects deadlock if another blocking commit is done by a client
notified from the single commit thread.

Change-Id: Icdc2b835fd336a1bbc37953828126b57253929c0
Signed-off-by: tpantelis <tpanteli@brocade.com>
Merge "Bug 1386: Avoid commit deadlock"