Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Merge "Fix DNS use for testcase 3"
  - Fix DNS use for testcase 3

    Make the VMs use properly 8.8.8.8 nameserver

    Change-Id: I8ebf0ff23fa78dcbc50eba9eb27262e690c56b66
    Signed-off-by: tomsou <soth@intracom-telecom.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index a720669..c0c5ba6 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit a720669923b555f348235076369479bb13571978
+Subproject commit c0c5ba6870a8e44c537c223aec8261587f39749b