Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Fix os-odl-bgpvpn-[no]ha scenario reference

    These shouldn't be prefixed with a '-' nor duplicated.

    Change-Id: I88f5b2d18436a258d6ac573a1fbc6dee735b48da
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index b1c8323..705e5cb 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit b1c8323dcd962b456da0438df65b4a37bb12f3d7
+Subproject commit 705e5cbf70c5937a841b58fc484ce0ee2e51a351