Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add support for review jupyter notebook from nbviewer"
  - Add support for review jupyter notebook from nbviewer

    It is done by uploading the notebook under reviewer to artifacts
    and add the nbviewer link in gerrit comments

    It is needed because reviewing jupyter notebook[1] directly in
    gerrit is very difficult. See example in [2]. It will be much
    easier if we can preview the result in nbviewer. See example in [3]

    [1]: http://jupyter.org/
    [2]: https://gerrit.opnfv.org/gerrit/#/c/37227/
    [3]: https://nbviewer.jupyter.org/urls/git.opnfv.org/qtip/plain/examples/storage-qpi-report/storage-qpi.ipynb

    Change-Id: I3e4c301f362ff6ac97aebc9d09c7103278efb136
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>