Remove dir_mode from rabbit key distribution

Setting dir_mode to 0750 prevents rabbit from reading /etc/rabbitmq as
the owner and group are root.

This patch removes the dir_mode paramter so that the memcahed module's
default of 0755 is used.

Closes-Bug #1506992

Change-Id: I3936a6bf181e3cf3f22b712d16d9181017f949cd
(cherry picked from commit f665acc)

playbooks/roles/rabbitmq_server/tasks/rabbitmq_ssl_key_distribute.yml

@@ -19,12 +19,11 @@
     file_path: "{{ item.src }}"
     state: "retrieve"
     file_mode: "{{ item.file_mode }}"
-    dir_mode: "{{ item.dir_mode }}"
     server: "{{ memcached_servers }}"
     encrypt_string: "{{ memcached_encryption_key }}"
   with_items:
-    - { src: "{{ rabbitmq_ssl_cert }}", name: "rabbitmq_ssl_cert", file_mode: "0640", dir_mode: "0750" }
-    - { src: "{{ rabbitmq_ssl_key }}", name: "rabbitmq_ssl_key", file_mode: "0640", dir_mode: "0750" }
+    - { src: "{{ rabbitmq_ssl_cert }}", name: "rabbitmq_ssl_cert", file_mode: "0640" }
+    - { src: "{{ rabbitmq_ssl_key }}", name: "rabbitmq_ssl_key", file_mode: "0640" }
   register: memcache_keys
   until: memcache_keys|success
   retries: 5