Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Remove unused files in udp replay

    Change-Id: I8cbad85c607ca5148723ed3689eaed2c4967fb1d
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index c5dfa2b..c26833c 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit c5dfa2ba7c21dac5ff6895f6e0fa2dc1dcc50cc1
+Subproject commit c26833c5007dadcd236e4b215790743fb137c9ec