Fixing /etc/rabbitmq permission bug

A change from the "Remove dir_mode from rabbit key distribution" commit caused
a bug where non-primary RabbitMQ containers would keep /etc/rabbitmq
permissions set to 0750 (the default is 0755).  This prevented the plugins
file from being read and it broke queue mirroring.

This patch ensures that the default permission of 0755 is set on RabbitMQ
and should prevent problems with future upgrades.

Closes-bug: 1513668

Change-Id: I62d6b09dad0eef0d9543442bb727f6c946d8738e

playbooks/roles/rabbitmq_server/tasks/rabbitmq_ssl_key_distribute.yml

@@ -41,3 +41,16 @@
     - "{{ rabbitmq_ssl_cert }}"
   tags:
     - rabbitmq-ssl
+
+# This is here because there was a different way of configuring SSL/TLS
+# for RabbitMQ that used a mode of 0750 for the RabbitMQ directory.  That has
+# since been updated but we need to ensure that old environments get this
+# critical update during upgrades.
+#
+# See bug 1513668 in Launchpad for more details.
+- name: Ensure /etc/rabbitmq is set to the default mode of 0755
+  file:
+    path: /etc/rabbitmq
+    mode: 0755
+  tags:
+    - rabbitmq-ssl