Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "KVMFORNFV: Reverting LiveMigration changes"
  - KVMFORNFV: Reverting LiveMigration changes

    This patch consists of reverting the changes of patch 45227 and
    incudes redirecting the console output of the LiveMigration
    execution to /dev/null as the stdout contains only the statistics,
    i.e., totaltime, downtime and setuptime.

    This reverts commit 5a1f65d3e7d67488ee6f558dccfa5ca5581ddb65.

    Change-Id: I252b5a4045657cfa8362e9aae755249480cd3b77
    Signed-off-by: Navya <navyax.bathula@intel.com>