Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'stable/danube'
  - yardstick offline support

    JIRA: YARDSTICK-597

    Currently yardstick can not run offline.
    In some case this will block the process, causing yardstick job failed
    The reason is yardstick will pull the latest code when run in CI.
    Actually we need not pull the latest code because the code in yardstick
    is already the latest code.
    So I remove them.
    Also I check the environment variable and yardstick-image when fetch
    openrc file and load images.

    Change-Id: I797da272932ab5292aa40585c82c119aa71b8849
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>
    (cherry picked from commit 38df788fc4a683717a6e7cbd498fad1e7cbe7209)