Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Fix Expermental JJB Job Diff Commenting"
  - Fix Expermental JJB Job Diff Commenting

    This change fixes the following issues:
    1) 'nounset' will cause the script to fail when activating a virtualenv
       since the activation of a virtualenv unsets variables
    2) There are not artifacts available from releng-merge-jjb and copying
       them would save minimal time over re-running jjb

    Change-Id: Ifc4297947c8fe235987a507ead932841480165a7
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e19f035..23bd33c 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e19f03540368a5d3f78e6a2d856a91cf52892414
+Subproject commit 23bd33c54e69205afb5349aee9ee310f2f66ed6c