Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Install docker-py when running xci as part of CI"
  - Install docker-py when running xci as part of CI

    docker-py package is required by the docker_container module in ansible:

    http://docs.ansible.com/ansible/latest/docker_container_module.html#docker-container

    Change-Id: Ib051ae09c84cfa973ef814852e78626499471d0f
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index d1864b3..a934224 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit d1864b34391a0965120bbb5162a17abaa6a8e7fc
+Subproject commit a934224aed505efe524a9a4c2db3b917e5addfef