Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - xci: Change cinder backend and move nfs to compute00

    This change
    - switches cinder backend from lvm to nfs as examplified in [1].
    - moves nfs shares from compute01 to compute00 in order to merge
    configure-targethosts.yml playbook in upcoming change.
    - updates openstack_user_config.yml to reflect the switch to nfs
    and move of nfs server to compute00.
    - removes exports file due to switching to lineinfile module.

    [1] https://docs.openstack.org/project-deploy-guide/openstack-ansible/draft/app-config-prod.html

    Change-Id: I0715c98a89ab124256e3857c1047e374f261e39b
    Signed-off-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>