Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "modules.opnfv: fuel adapter: Switch to MCP"
  - modules.opnfv: fuel adapter: Switch to MCP

    The current codebase was intended for Fuel@OPNFV up to and including
    the Danube release (based on Fuel@Openstack).
    Starting with the Euphrates release, Fuel@OPNFV is based on Mirantis
    Cloud Platform (MCP), so the Fuel adapter in modules.opnfv needs a
    rework to accomodate the new platform:
    - remove unused obsolete code in opnfv.utils;
    - switch to key-based SSH auth instead of password-based;
    - drop proxy-ing SSH to cluster nodes via installer node, instead
      SSH directly via PXE/admin network;

    Notes:
    - MaaS node (when present) is marked with 'installer' role to prevent
      ovs-vsctl queries on it;
    - gtw01 node (when present) is not marked with any role yet;

    JIRA: FUEL-394

    Change-Id: If2b7744b950cd502df8eaca0137c9f845a9d077d
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>