Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Enable jobs for stable/euphrates branch"
  - Enable jobs for stable/euphrates branch

    Change-Id: I9c9759f3f361d6e0e56429e0aeca6205fa59934f
    Signed-off-by: Zhijiang Hu <hu.zhijiang@zte.com.cn>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f9f7289..cf7a4aa 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f9f7289953029b9d9b0765a8647fc0e847975879
+Subproject commit cf7a4aa78910d8c401d018a769863097e63b7f4a