Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "xci: scripts: start-new-vm.sh: Use Docker to build OS images"
  - xci: scripts: start-new-vm.sh: Use Docker to build OS images

    Use a docker container to build the OS images so we can build images and
    start new virtual machines on all supported operating systems. This way
    all developers can now launch a virtual machine to quickly reproduce
    Jenkins results which should assist with debugging problems.

    Since the container runs with elevated privileges it's best to ensure
    that we have exclusive access to devices. Finally, we remove the
    build-dib-os.sh script which is now part of the container itself.

    The build image process now becomes more stable since it runs on clean
    evnironment all the time so the only external factor is the upstream
    distribution repositories.

    Change-Id: I6b443192419ee2546a23430f421b152766d16333
    Signed-off-by: Markos Chandras <mchandras@suse.de>