Added cluster aware mdsal utils class to net-virt (redo)

Added cluster aware mdsal utils class to net-virt (redo)

Looks like while code cleanup we removed the MdsalUtils.java from the master branch
and while merging master branch to net-virt-clustering, it got removed as well.
Net-virt-clustering had a modified version of MdsalUtils.java, where put/merge/delete
transactions are only done by the master instances of net-virt. ClusterAwareMdsalUtils
class bring those changes back.

Patch set 2: Explicitly callback into OvsdbInventoryService when netVirt becomes owner.
Patch set 3: Undo patch set 2; make ProviderEntityListener to happen earlier

Change-Id: I42ab5f2969bcff7737d90f2651d2762897e74c9a
Signed-off-by: Anil Vishnoi <vishnoianil@gmail.com>
Signed-off-by: Flavio Fernandes <ffernand@redhat.com>