Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Add subproject INFO.yaml"
  - Add subproject INFO.yaml

    This change adds INFO.yaml for releng-xci Gerrit Project which is
    constructed by subset of committers of Releng project who are active in
    xci. New committers to releng-xci Gerrit Project will be nominated
    on Gerrit via separate changes and voted by releng-xci committers that
    are listed within releng-xci/INFO.yaml file as of today.

    A single mail with all the nominations will be sent to opnfv-tsc and
    opnfv-tech-discuss mailing lists announcing nominations. A followup
    mail will also be sent to announce the results.

    Change-Id: I1d49585276304b29ac86b03aff5fd45974a02ccc
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>