Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Disable git tagging during Jenkins git clone"
  - Disable git tagging during Jenkins git clone

    Even with per-build-tag set to false, JJB 1.6.2 does not seem to remove
    'Create tag for each build' from the git-scm settings. Though the option
    is deprecated it is still supported, so setting both of these should
    disable tagging when Jenkins clones a git repo.

    Change-Id: I5977149ad581df67d938ce2b46794d47c5e06fe3
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f077491..bffc847 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f0774918777561fd00c996438436c2ef7f4d67ff
+Subproject commit bffc84719fb9846add3794e33f3e375b0f3c664b