Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "xci: scripts: start-new-vm.sh: Fix ID for openSUSE Tumbleweed"
  - xci: scripts: start-new-vm.sh: Fix ID for openSUSE Tumbleweed

    Recent openSUSE Tumbleweed releases are now using 'opensuse-tumbleweed'
    as distro ID so we need to take that into consideration in order to be
    able to use the script on such systems.

    ~$ source /etc/os-release && echo ${ID}
    opensuse-tumbleweed

    Change-Id: Ibdfb4292d53dc4d20376230a4131b212f9492e54
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index ade43f7..c6845a7 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit ade43f7f3c6503378ff375043b262425361d335f
+Subproject commit c6845a788029dd7b5985f566a1a6d63a711a8e9d