Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Create specific flavor for neutron-l3-agent HA test

    The neutron-l3-agent test assumes that a default image and flavor are
    available. On current OPNFV deployments, these resources do not exist
    anymore by default and hence the test case fails.

    This patch enables Dovetail to create a specific flavor as part of the
    test case config. This is temporary workaround until the test case
    itself takes care of checking and creating all resources needed. A
    ticket for the HA project has been created accordingly:
    https://jira.opnfv.org/browse/HA-36

    Change-Id: I6523d8411fe853a5645566b2fabe1409b5715491
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>