Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Clean always and change order

    Change-Id: Ic9e0d374a4fe5278888b28fe2694c546840d55b4
    Signed-off-by: Nikolas Hermanns <nikolas.hermanns@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 9e47ddb..88331de 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 9e47ddb9739bb3e6b2ca91615c71bcd94c954172
+Subproject commit 88331de3fb9375d316acba7b160ddf2a9beab5b2