Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "jjb: xci: bifrost-verify.sh: Do not build OS images"
  - jjb: xci: bifrost-verify.sh: Do not build OS images

    Use the images we provide in artifacts.opnfv.org instead of
    building new ones on every CI run. Moreover, enter the correct
    directory before executing the CI script.

    Change-Id: Iffa0080ab8f746344aa13bca6a26395a8a0953f2
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 3700696..9062684 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 3700696bfc796d9c560c4605759dda1df9f44b30
+Subproject commit 90626845ce539254abbcf5ecb96d287ddd5c8fb5