Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Use CONST to retrieve db_url rather than getter function"
  - Use CONST to retrieve db_url rather than getter function

    1. Remove get_db_url()
    2. If TEST_DB_URL declared in env, update test_db_url in
       config_functest.yaml file during env preparation
    3. No matter TEST_DB_URL declared in env or not,
       Result_DB = CONST.__getattribute__("results_test_db_url")

    JIRA: FUNCTEST-763

    Change-Id: I20da7ef98bbcc56731e0ff7061b05c1dde6cbfc3
    Signed-off-by: Linda Wang <wangwulin@huawei.com>