Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add image extra properties for fuel installer in functest test"
  - Add image extra properties for fuel installer in functest test

    With using scsi volume device type, additional image
    extra_properties are needed.
    Set environment variable IMAGE_PROPERTIES when installer is fuel for
    functest test run.

    Related to:
      https://gerrit.opnfv.org/gerrit/#/c/61913/
      https://gerrit.opnfv.org/gerrit/#/c/63225/

    Change-Id: If35aa282abaf5dab1a5bacc2f26fe89292b09605
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>