Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove 'cd && pull' commands from jjb-merge job"
  - Remove 'cd && pull' commands from jjb-merge job

    These are no longer needed since the server has been migrated, and a git
    clone already exists in the workspace.

    Change-Id: I07b5ff9185323d7295578b23a634e2d0e03afcd7
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 43cf1bb..d4851ff 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 43cf1bbc859d4be16bfc5e91aba2c8782ca4677e
+Subproject commit d4851ff5ac133c2672dfe1ed806a57c1c0abaa63