Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Remove 'inconsistent-return-statements' check from Pylint

    There are several bugs in Pylint [1] [2] affecting
    'inconsistent-return-statements' check. It will be temporarily
    removed.

    [1] https://github.com/PyCQA/pylint/issues/1782
    [2] https://github.com/PyCQA/pylint/issues/1794

    JIRA: YARDSTICK-911

    Change-Id: Ib655ef1befdc734c646cdfb9b48f1db0ccdf676d
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>