Need an extra package if we're using debian for rabbit clustering.

playbooks/roles/rabbitmq/tasks/main.yml

@@ -6,6 +6,10 @@
 - name: trust rabbit repository
   apt_key: url={{rabbitmq_apt_key}} state=present
 
+- name: install python-software-properties if debian
+  apt: pkg='python-software-properties' state=present
+  when: ansible_distribution == 'Debian'
+
 - name: add rabbit repository
   apt_repository: repo="{{rabbitmq_repository}}" state=present