Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Adding dpdk version for non-interactive vnf_build options.

    Change-Id: I95c6778fd216c6f7e3eee97c83f93726bb4298d0
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 7286b25..27c68de 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 7286b2518ec8e4398b512ce95def9166a7af2e4a
+Subproject commit 27c68de1ca5795173e96e55c161c0c9572d32626