We don't seem to need.

We install the rabbit deb from files.edx.org

I was able to install rabbit and all of its apps at the same
version we have in production without adding the rabbit PPA.

playbooks/roles/rabbitmq/defaults/main.yml

@@ -29,8 +29,6 @@ RABBITMQ_CLUSTERED_HOSTS: []
 # option to force deletion of the mnesia dir
 rabbitmq_refresh: false
 
-rabbitmq_apt_key: "https://www.rabbitmq.com/rabbitmq-release-signing-key.asc"
-rabbitmq_repository: "deb http://www.rabbitmq.com/debian/ testing main"
 # We mirror the deb package for rabbitmq-server because
 # nodes need to be running the same version
 rabbitmq_pkg_url: "http://files.edx.org/rabbitmq_packages/rabbitmq-server_3.2.3-1_all.deb"

playbooks/roles/rabbitmq/tasks/main.yml

@@ -3,15 +3,9 @@
 # There is a bug with initializing multiple nodes in the HA cluster at once
 # http://rabbitmq.1065348.n5.nabble.com/Rabbitmq-boot-failure-with-quot-tables-not-present-quot-td24494.html
 
-- name: trust rabbit repository
-  apt_key: url={{ rabbitmq_apt_key }} state=present
-
 - name: install python-software-properties if debian
   apt: pkg={{ ",".join(rabbitmq_debian_pkgs) }} state=present
 
-- name: add rabbit repository
-  apt_repository: repo="{{ rabbitmq_repository }}" state=present update_cache=yes
-
 - name: fetch the rabbitmq server deb
   get_url: >
     url={{ rabbitmq_pkg_url }}