Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: Move cleanup script outside of bifrost

    The cleanup script has grown quite a bit over time and it now does more
    things than cleaning up old 'bifrost' artifacts to move it to the global
    files directory so it can be used by all installers.

    Change-Id: Ibf70ff255f14e798216cedc71fb7c5f5476b964a
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 346df57..e47cdad 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 346df57c53fde3795fbe675477cdb2c1a453b6f7
+Subproject commit e47cdad33ce29f7db4e0cb72c323ed63504afe16