Update git submodules

* Update docs/submodules/samplevnf from branch 'stable/euphrates'
  - Merge "Docs: Developer guide review and update" into stable/euphrates
  - Docs: Developer guide review and update

    Review and update teh Developer guide for E-Release.

    Change-Id: I5bb2626cb3f69953b741cd46ea584423756786f2
    Signed-off-by: Anand B Jyoti <anand.b.jyoti@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index e511ac9..16b4c6a 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit e511ac90dd0415ae4c57e6b0c706cfb8a051c081
+Subproject commit 16b4c6a773018a9235aaf99ea31d6f8b53261504