Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/euphrates'
  - Fixing argument error

    Cherry-picking https://gerrit.opnfv.org/gerrit/#/c/43399/ to
    stable/euphrates for use in Dovetail.

    Change-Id: I871d73d2483919b4c3ef4929380c2501383dabce
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index d81779d..a2f6324 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit d81779daee14b1567f4f4a0a55509c8ba35909d4
+Subproject commit a2f632467606d479ad0b44a1884b9a28d8f87106