Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove euphrates jobs"
  - Remove euphrates jobs

    Change-Id: Icf57ec3e65e391207333bb8780ea215bcf4434a4
    Signed-off-by: agardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b513580..8d84d7d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b5135804de0091e03ff9f4633cdc1c66d8ceb752
+Subproject commit 8d84d7d9ac290135804b8ab3f5506e175db8d29e