Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Running Test Case in Latest Yardstick Docker Image shows Error"
  - Running Test Case in Latest Yardstick Docker Image shows Error

    JIRA: YARDSTICK-1080

    This bug will only occur in kubernetes test case.
    In openstack, we use 'stack_name.context', but some kubernetes
    resources(pod, etc) do not support this format. So we use
    'name-context'.

    Change-Id: I87d61c027d55449914bc283672eb98be3d3fe22f
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>