Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - remove testing docs

    Change-Id: I76af05c6b3dbd945d4c027ea3dc58ae1e5357418
    Signed-off-by: Nikolas Hermanns <nikolas.hermanns@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index c063e49..a8ac068 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit c063e49cec6afa6ba1ab743a86482768fe1cc28e
+Subproject commit a8ac0683dc4accfc4d300de20071989c0d1ffb63