Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/fraser'
  - create log file only if it doesn't exist

    Change-Id: I97e4f0cf8f27ff719253967ac14e74bcd55b0559
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>
    (cherry picked from commit 9df57f96b44d41c98a556a790dfa7f96b8dc9808)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index bb3a70f..5c5eaf2 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit bb3a70fc7b8b8c880f86b7853568d61e308a9063
+Subproject commit 5c5eaf22dfe1f439866709712b06c76129fe16eb