Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Improve the way of setting values in CONST"
  - Improve the way of setting values in CONST

    Use setattr instead of internal method (__setattr__).
    It must be completed by patches fixing [1] [2] and [3].

    [1] https://jira.opnfv.org/browse/FUNCTEST-930
    [2] https://jira.opnfv.org/browse/FUNCTEST-931
    [3] https://jira.opnfv.org/browse/FUNCTEST-932

    Change-Id: I9558f33f5ed4559b6031d75951d5637c0c0ef8cb
    Signed-off-by: Linda Wang <wangwulin@huawei.com>