Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "jjb: xci: xci-verify-jobs: Export clean vm variables properly"
  - jjb: xci: xci-verify-jobs: Export clean vm variables properly

    The variables are meant to be used by the start-vm-new.sh script
    instead of the XCI test so they need to be exported properly before
    we run the script.

    Change-Id: I224ec7bfced5eb51f01de46bd042274bcf3ec86b
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 6ebcae5..19f559f 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 6ebcae56c76492c4cdf42141a7b60bae1991e6f3
+Subproject commit 19f559f63eed668fcfa4d7ded964a635eb52a769