Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Merge "Route exchange test with testcase3"
  - Route exchange test with testcase3

    This review brings up quagga VM installed with 6WIND quagga,
    configures with external ip prefix and making sure that it gets
    exchanged with ODL peer.

    Change-Id: I9ba677e74f24258f7cc59db70b013fbdbbec917a
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 85fc784..643764b 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 85fc78459cb3e3df72a6cb5c793d19ae41ddd7dd
+Subproject commit 643764bf5b65d837d424df278015f8cfb535a3ad