Update git submodules

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

    Change-Id: I5e5f66b1226291934fecca6fcf83dd649fb82f0e
    Signed-off-by: agardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index eceb323..4ee0e09 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit eceb32353cf400e52a13d35ecb5987ba94341872
+Subproject commit 4ee0e0934a6181866cdea70a9bb0c05728e31c7f