Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Install RabbitMQ service in Yardstick functional tests"
  - Install RabbitMQ service in Yardstick functional tests

    Install and configure RabbitMQ service for Yardstick functional
    (Python 2.7 and Python 3) tests.

    JIRA: YARDSTICK-1104

    Change-Id: I6b287def05c75dc67ab21727f72d4c384f8e2837
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 3f7ed73..3ec4f93 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 3f7ed739246588580bb41e608e67a8f8d663d30d
+Subproject commit 3ec4f930f4ab7910ce730b4648f2a7403711cdcd