Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - use glance_client for image cleanup

    Change-Id: Ia192a1b26c5f31b6d3465a060c3d8a3097e6ebd4
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 8211ebd..f3d22e6 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 8211ebd59a28be997386030cb1f87e0630770a78
+Subproject commit f3d22e693075fc40ed392f4d1345a81c84bf34c4