Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Fix the offset bug for UDP dst port in the traffic profile

    Also sends a new line to the VNF when waiting for prompt.

    Change-Id: Ib8641093974cd6713594aac9b418595ad5268e87
    Signed-off-by: Martin Banszel <martinx.banszel@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 3016786..3aff7e9 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 3016786696b9e5a26b364cb5bd4cb5676420fe58
+Subproject commit 3aff7e97749b898d5022b1d3e5e9106cecca3113