Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Remove setup_env for refstack in Dockerfile

    It creates a symlink for .tempest required by refstack, and then
    install the requirements of tempest into a virtualenv which
    should be located in the dir .tempest/.venv.

    Now refstack_client is located in /src like tempest to avoid a link
    in /usr/local/lib/python2.7/dist-packages.

    JIRA: FUNCTEST-846

    Change-Id: I99cedd00daaac57f85532ef41b91da20dec3dcb8
    Signed-off-by: Linda Wang <wangwulin@huawei.com>