Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "xci: Add ansible files for sandbox mini flavor"
  - xci: Add ansible files for sandbox mini flavor

    This patch adds mini target host configuration playbook, inventory, variable
    files and so on to use until we have time to fix things more properly and some
    other functionality becomes available in upstream. This approach will result in
    duplicates but it is something we can perhaps live with.

    The user variables and openstack user configuration will be different between
    flavors and keeping deployment specific configuration.

    Change-Id: Ie312dfa2047d094b590de970c1436d69f4c69668
    Signed-off-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>