Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Configure password for the user in vnf

    For some SUTs, the password for creating user is not allowed to
    be the same as user name, and some even is required to contain
    at least 8 characters and three types of characters for security.

    It also turns yamllint warnings into errors and fixes the remaining
    warnings.

    Change-Id: Icf25a7b9ff1c8cee55899198f1e519c9209877ff
    Signed-off-by: Linda Wang <wangwulin@huawei.com>