Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "xci: Reconfigure xci-daily-virtual jobs"
  - xci: Reconfigure xci-daily-virtual jobs

    The execute shell parts need to be switched to existing
    scripts but since the scripts were mainly written for
    verify jobs, the adaptations they require has potential
    to cause issues so it needs to be done in a separate
    change.

    Apart from that, the verify and daily jobs can't be run
    on same slave at the moment due to a bug in opnfv vm
    creation playbook. If clean vm exists on the node, the
    playbook fails. Build blocker is enable for verify and
    daily jobs to ensure the jobs don't end up on same slave
    for the timebeing.

    Change-Id: Iefaf5a5c2d4a79bd48a5f9da28d68748bc67f511
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a2fb2e4..6b631d7 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a2fb2e42e1ffedcc3d22309ed08d9f96deb099f4
+Subproject commit 6b631d71668db9d4bde2fb3ef517235e579faa45