Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Improve ovs_deploy.bash script"
  - Improve ovs_deploy.bash script

    Improved ovs_deploy.bash script [1]:
    - Check if there is an error during the execution.
    - Removed "prerequisites" function because is not called.
    - Modified DPDK package installation: execute "make config" and then "make"
    - Added comments.

    [1]https://github.com/opnfv/yardstick/blob/master/yardstick/resources/scripts/install/ovs_deploy.bash

    JIRA: YARDSTICK-916

    Change-Id: I3029f983dde72aa46f6fdd61dd64d086ab3c2af6
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>