Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: scripts: start-new-vm: Use host-passthrough to use the real host CPU

    The host-passthrough mode will allow the VM to use all the host cpu
    features so it should provide the best possible CPU performance.

    Change-Id: I6ecd0363d046aaefa08f9e97144aa9ca9f1afae5
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 39d9f4d..6c728e2 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 39d9f4db802ade0b8be8216ae124b1f42f7a7a78
+Subproject commit 6c728e29fee8e36b8ad66964e13ed2b311ef7bee