Updated git submodules

Updated git submodules

Project: netvirt master 718e81fc8017332e6fc9e5b7a5d13cdae950863e

Remove unused NatNodeEventListener

This listener does not have anything else other than debug statements.
This was seen while analyzing the delay in programming default flows
when switches are connected in scaled scenario. While trying to optimize
the number of listeners and heavy operations being done in listener
thread, this came to notice. There is no heavy operation here, but if
the listener is of no use, let us avoid one unnecessary registration.

Change-Id: I87f80b851472dba7364fe16c5d39d8ed775b2d67
Signed-off-by: Faseela K <faseela.k@ericsson.com>