Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/fraser'
  - Merge "Make sdnvpn logging proper" into stable/fraser
  - Make sdnvpn logging proper

    * Currently no log messages are getting written into log file due to
    file handler is registered for logger object created at different
    modules. Now corresponding handler is registered for logger objects.
    * Making sdnvpn Feature class to use its parent class logger object to
    avoid unnecessary logger object creation.

    Change-Id: I4ec61951ba4ac39cecc137dbb818da72f0b43b35
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>
    (cherry picked from commit 303268d0464127c52f11443404fb1baae03d615f)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index be6cce3..23ec591 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit be6cce375c0363f93fa6b1a099eb34fee75a6161
+Subproject commit 23ec5914be722401dcbc2ceb9f4be1491c150776