Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: file: ansible-role-requirements.yml: Bump SHA for lxc_hosts

    Bump the SHA for lxc_hosts so we can start using lxc-2.X.X on SUSE
    hosts.

    Change-Id: Ia4830996a66b5694a9d22f8cd067ca12163939a3
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 21a82ce..564dce0 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 21a82ce0689793f85777ea1be65c8c068f0dabd4
+Subproject commit 564dce0ef905b395e1e2377d4d940bb56af7468f