Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "dovetail: conditional steps added to fuel-bgpvpn scenario"
  - dovetail: conditional steps added to fuel-bgpvpn scenario

    JIRA: DOVETAIL-432

    1, only run against fuel os-odl_l2-bgpvpn-ha scenario
    this can reduce the CI/pod time resource
    dovetail test cases by now (refstack, ha, ipv6, bgpvpn)
    2, the conditional steps have been successed tested on compass
      to remove the introduce of
      https://gerrit.opnfv.org/gerrit/#/c/34327/
      conditonal steps look more simple and understandable

    Change-Id: I315a789160b8173274b1c1ef916073ced7d5e91b
    Signed-off-by: MatthewLi <matthew.lijun@huawei.com>