Updated git submodules

Project: netvirt master d2517c30e3377e4f21f0d10683b357d933f929fe

Bug9016:Using Single Transaction during NAPT SwitchOver

Problem Description:
====================
When NAPT Switch over happens, multiple transactions were made to remove
SNAT related flows from Primary NAPT switch and reinstalling flow on new
NAPT elected switch.

Optimization needs to be done to make use of single transaction taking
care of removing all SNAT related flows from old NAPT and another single
transaction for installing SNAT flows on new NAPT switch.

Solution:
==========
Used one write transaction object for used to remove all NAPT related
flows from old NAPT switch during NAPT switch over happened. Used other
write transaction object for installing all NAPT related flows on newly
elected NAPT switch. This will reduce the number of transaction object
were used during NAPT switch over happens as well as installing SNAT
related flows during first time as well.

Note:
=====
Have removed ExternalNetworkListener.java class. Since this class was
taken care for installing NAT default flow L3_FIB_TABLE(21)
PSNAT_TABLE(26) on all NAT switches. This same logic was already
implemented in ExternalRoutersListener class. Just to avoid the conflict
modification error, removed ExternalNetworkListener.java class from NAT
Module.

Change-Id: Ic2b54e7acbb01805b9a25fea28017c7353ee59d2
Signed-off-by: karthikeyan <karthikeyan.k@altencalsoftlabs.com>

diff --git a/docs/submodules/netvirt b/docs/submodules/netvirt
index 96e11c3efe8726cdf482328f9637a0468d59daae..d2517c30e3377e4f21f0d10683b357d933f929fe 160000 (submodule)
--- a/docs/submodules/netvirt
+++ b/docs/submodules/netvirt
@@ -1 +1 @@
-Subproject commit 96e11c3efe8726cdf482328f9637a0468d59daae
+Subproject commit d2517c30e3377e4f21f0d10683b357d933f929fe