Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - xci: Clone the repo and checkout the patch for testing

    Change-Id: Ie1c2f76b6043133c3821272040b1a2a38de29035
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>
  - xci: Always clone releng-xci into WORKSPACE for merge jobs

    The cloning of the correct version of the repo which the scenario
    resides in will be handled by get-opnfv-scenario-requirements.yml
    for all the scenarios.

    The change proposed for merge jobs will be reflected to verify jobs
    as well once it is verified with this.

    Change-Id: Icaa99a8b9e981c839969ce556e5af6a9ef6d9da8
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>