Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Dovetail failed to archive tempest.log and tempest-report.html files

    It failed to archive tempest.log and tempest-report.html files.
    See CI results
    https://build.opnfv.org/ci/view/dovetail/job/dovetail-compass-baremetal-default-mandatory-fraser/7/artifact/results/

    That's because the path of them have been changed
    1. from tempest to tempest_custom
    2. from refstack to refstack_defcore

    There seems to be no file bgpvpn.log, remove the copy operation.

    JIRA: DOVETAIL-714

    Change-Id: I77d88124a44d3e5d869ada209760f69d1f6553bf
    Signed-off-by: xudan <xudan16@huawei.com>