Update git submodules

Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Nomination of Tianwei Wu as XCI committer"
  - Nomination of Tianwei Wu as XCI committer

    Tianwei Wu made many important contributions to XCI which includes but
    not limited to
    - bringing up first prototype for XCI using OpenStack Ansible
    - assisting others with the usage of prototype
    - bringing Kubespray to XCI
    - developing Kubernetes scenario k8-nosdn-nofeature which can be deployed
    on multiple Linux Distributions, Ubuntu 16.04 and CentOS 7
    - updating documentation
    - reviewing changes

    His contributions can be seen from following link:
    https://gerrit.opnfv.org/gerrit/#/q/owner:wutianwei1%2540huawei.com+(project:releng-xci+OR+project:releng)+status:merged

    Please note that XCI started in OPNFV releng repo and some of his
    contributions were made while XCI was still developed in releng repo.

    Change-Id: I8d7b802a13a0ce1f7eb87ab5811437419572d823
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>