Update git submodules

* Update docs/submodules/samplevnf from branch 'stable/euphrates'
  - Updating user guide

    Change-Id: I80bcbe616b8f2c64151de6e588c892de6c3dc8f1
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 833b18a..bdf826f 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 833b18a279ff8788885820bbbf779f0a4163c68a
+Subproject commit bdf826f13c9b3b3c0d1b8e0028dad653ef69d9fc