Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "prototypes: bifrost: Write clouds.yaml file for regular users"
  - prototypes: bifrost: Write clouds.yaml file for regular users

    This is similar to commit 6769ae9bcbf6 ("prototypes: bifrost: Add
    keystone roles"). In preparation for running the bifrost jobs as normal
    user we need to write a clouds.yaml file to users home directory.
    This is similar to the bifrost upstream testing playbook.

    Change-Id: Iae4bc73906649707667925280a19282ec5c93998