Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: synchronize-time: Install the chrony package and drop Xenial reference

    The roles should pull all the packages they need so we need to install
    the 'chrony' package everywhere and also drop the Xenial reference since
    there is nothing Ubuntu specific here.

    Change-Id: I51fb24573c0e884f8a96868e304b23140cc23b41
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 725e250..3133644 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 725e250ad2d36697487df629002a7caa7114c6d3
+Subproject commit 313364481b13da8b09242d7275c52192d3e3438e