Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: Add OS variables to the post-deployment playbook

    OSM needs access to OpenStack credentials and authentication url.
    This patch would provide that using the xci_flavor specific
    user_variables.yml file. This patch is necessary to complete the
    initial integration of OSM.

    installer-type:osa
    deploy-scenario:os-nosdn-osm

    Change-Id: Ic228b323fc69ce46c8093f6dfbc116d8c71a0391
    Signed-off-by: Venkata Harshavardhan Reddy Allu <venkataharshavardhan_ven@srmuniv.edu.in>