Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Adding log gathering

    Change-Id: I0f13e5aa8aea25e549c9ffede63085a86153cdba
    Signed-off-by: Nikolas Hermanns <nikolas.hermanns@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 74db571..3668645 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 74db571092ab8650d8059430ea4e4033d2269527
+Subproject commit 3668645d06669e0abe44535ee3a4450a0b83709c