Update git submodules

* Update docs/submodules/samplevnf from branch 'stable/euphrates'
  - remove unwated proxy in the script

    Change-Id: I4a38ac4f7a05b6a96fd9e0e8539aa76252ded3b0
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index d9a3436..833b18a 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit d9a3436d10beda19e3a9d6d630f56671d1d5d1e9
+Subproject commit 833b18a279ff8788885820bbbf779f0a4163c68a