Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "jjb: xci: Run bifrost provisioning as normal user"
  - jjb: xci: Run bifrost provisioning as normal user

    Ansible can request elevated privileges using the 'become' directive.
    As such there is no need to run ansible using sudo. Furthermore,
    OpenStack CI runs all jobs as normal user and we need to do the same
    in order to compare behavior and results properly.

    Change-Id: Id198efd1d6fdf4619de931fbedc7caba8d68d2a0