Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Detach quagga vm in the cleanup block

    Change-Id: I45145dacaeec0f7b518ab61a33d3a824458e9af5
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 643764b..4b66304 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 643764bf5b65d837d424df278015f8cfb535a3ad
+Subproject commit 4b6630459f3cebb78ee21922f7976820ab04690b