Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: Use the dib pip-and-virtualenv element

    The element will ensure that we have a reasonable set of pip
    and virtualenv packages in place as well as pick the right
    python version for the distribution. We also make sure that
    we use python2 everywhere.

    Change-Id: I8a83af9acffbd8d6d583832956e1685100ec508a
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index b8791a5..4689cac 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit b8791a548b1845691068830679b5fa8855def6e5
+Subproject commit 4689cace9d3aa67d24d740201f1cb4ab29d930d8