Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Create Stable Branch Jobs for doctor"
  - Create Stable Branch Jobs for doctor

    Change-Id: I5705b961d4b6871325a071c6287650cc195f5fe6
    Signed-off-by: jenkins-ci <jenkins-opnfv-ci@opnfv.org>
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 30d28af..9cef18b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 30d28af772d4da598ccfd608b9ac24561de60f8c
+Subproject commit 9cef18bed3d594cd6c045c5a064f9914010ea2a0