Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Provide access to VM in Standalone context"
  - Provide access to VM in Standalone context

    Add possibility to access VM with SampleVNF image, which is spawned on
    baremetal server using password or key pairs (provided or generated).
    Changes provided for OVS-DPDK and SRIOV cases.

    JIRA: YARDSTICK-1260

    Change-Id: I89cf17dc83f02abe23d206b24b9d0ec1298d3231
    Signed-off-by: Stepan Andrushko <stepanx.andrushko@intel.com>