An atempt is made to reduce DS operations before fixed flows are

An atempt is made to reduce DS operations before fixed flows are
programmed for a VM

Below are change details:
(a) In AclInterfaceStateListener, DS operation to read Interface config
object was made all the time. Now, updated to check config Interface only
when AclInterface refernce is not present at that time (ie., with the
changes, config Interface is checked only when Interface state event is
triggered before Interface state event)
(b) After performing Port lookup DS write, current behaviour is to wait for
completion of this write operation. As what ever written to port lookup is
used only during delete operation, moved add/delete port lookup to a
separate thread with the same key using jobCoordinator. With this, Port
lookup DS write is unblocked and add/delete operation of it is also been
synchronized

Change-Id: Ic6300a82006d6a8c0db3ac7bb2168612a190697f
Signed-off-by: Shashidhar Raja <shashidharr@altencalsoftlabs.com>