Change notification processing to account for kernel changes

Change notification processing to account for kernel changes

   We now always get NEWLINK and DELLINK notifications for bridge port
   additions and deletions. And DELLINK is only for port deletions.
   So we can always remove a bridge port on a DELLINK notification,
   and not make uncertain checks in fear of missing this.

Signed-off-by: Srinivas Aji <Aji_Srinivas@emc.com>