Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Adding Security gateway testing"
  - Adding Security gateway testing

    Using now .test files describing the test to be executed.
    Also desribed in the README file how to deal with SRIOV ports.

    Change-Id: I3eb1551d7f205fef3fa1914bc6959c2126d63425
    Signed-off-by: Provoost <luc.provoost@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 6401ebd..25ffc70 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 6401ebd2b472a2402b640f4e8c773cc3d097093f
+Subproject commit 25ffc7091ffe7069e6b4aeed9a5a69aa034c58f9