Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Add functest healthcheck test suite

    - Add Functest healthcheck tier to Dovetail as new test suite
    - Intention is that these test cases are not part of mandatory
    test cases in compliance program
    - Use for debug and SUT pre-flight check
    - May consider running tc001 (connection_check) at other
    test execution stages to determine if SUT is still functioning, as
    this test takes < 10 sec (more important as test complexity increases
    such as in vnf test tier)
    - Replacement for patch:

    https://gerrit.opnfv.org/gerrit/#/c/52461/

    - Removed CI filters, as suggested

    Change-Id: I2e72931b27e43359d6250f6959a17af8526c5094
    Signed-off-by: Eddie Arrage <eddie.arrage@huawei.com>