Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/euphrates'
  - make CommonConfig as singleton

    * It is not necessary to instantiate CommonConfig object from each
    testcase and can be made as singleton

    Change-Id: I99d995486fbd88ea8a77ec7bd9e41a55047ebaca
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>
    (cherry picked from commit e7693b748e16f6013b5dddf6eb5ebcf9d0bb0a3d)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 8a20b43..963ad96 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 8a20b43bfb9723ae1f2410a5448363a5e3f38f7b
+Subproject commit 963ad969487d9896f126afadc8222c48460b81b2