Raise the file limit on the RabbitMQ cluster

RabbitMQ recommends[0] that the open file descriptor limit be set to a
minimum of 50K. It recommends that the maximum number of open
connections be multiplied by 2 and added to the total number of queues.
Finally, it suggests that 500K isn't an unreasonable setting. This sets
the default to 500K and makes the value configurable.

Signed-off-by: Jeremy Cline <jcline@redhat.com>

handlers/restart_services.yml

@@ -179,3 +179,9 @@
 
 - name: restart buildmaster
   service: name=buildmaster state=restarted
+
+- name: restart rabbitmq
+  systemd:
+    name: rabbitmq-server
+    state: restarted
+    systemd_reload: yes