Update git submodules

* Update docs/submodules/samplevnf from branch 'stable/euphrates'
  - vFW: changes for gateway packet forwarding

    JIRA: SAMPLEVNF-59

    Changes to support gateway packet forwarding to vFW.

    Change-Id: Ie9164b092f6864cfcdb02e7b325c4e8796a7e422
    Signed-off-by: Anand B Jyoti <anand.b.jyoti@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 6c01f30..9a780cc 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 6c01f3018228e2920d26235079ee40bd8a88f5b7
+Subproject commit 9a780cc221d28a0302555b89dd309087032b9e39