Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Update entry_point to conform with Xtesting

    Functest is being updated to Xtesting 0.60 which leverages on
    stevedore [1].

    [1] https://docs.openstack.org/stevedore/latest/

    Change-Id: Ic47a61b547ee41ca60c5d393f82c907ca27ba97a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 1fcda2f..64a5e7d 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 1fcda2f1a2d22f1161ab604841e819a1e1550116
+Subproject commit 64a5e7dc89be1c52253a48fb5ccfa045b6619d0f