Bug 2517: Catch RuntimeExceptions thrown from the DCL in DataChangeListener

This prevents akka from suppressing/dropping subsequent data change
events if a RuntimeException is propagated to akka.

Change-Id: Ibc90e00c56a3e3b6f0039ff609d639fe8201adf0
Signed-off-by: tpantelis <tpanteli@brocade.com>
Merge "Bug 2517: Catch RuntimeExceptions thrown from the DCL in DataChangeListener"