Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Fix PROX throughput result calculation"
  - Fix PROX throughput result calculation

    The success criteria needed a fix for throughput
    calculation. The results on success criteria were
    muliplied by 1000*1000 which is not correct and
    not needed as this was leading to false results
    in grafana.

    JIRA: YARDSTICK-1172

    Change-Id: I56b24a700f8a565db80897aeab796e7039cae5c9
    Signed-off-by: Abhijit Sinha <abhijit.sinha@intel.com>