Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Add fixes for heat deployed UDP_Replay and TRex

    - Added a PROTOCOL_MAP to map the protocol names to codes -- the scapy
      requires the code, it fails if the proto is set e.g. to 'udp'
    - ip addresses must be str, not unicode -- explicit conversion to str
      added
    - removed unittest for setup_vnf_environment in test_tg_trex.py as
      it is the same function as already tested in test_sample_vnf.py
    - traffic_profile refactored -- code repetition decreased, unittest
      adapted

    Known issues:
    - there is a an attempt to stop already stopped trex. It fires an
      exception that stop command is issued on the disconnected client.

    Change-Id: I87e9029630f48b30e8f5b4f9d88ab3b25fd65f03
    Signed-off-by: Martin Banszel <martinx.banszel@intel.com>