Remove jinja delimiters in when

Change-Id: Ib6a544b2d863fe3bc2f8fafa7ca0fbb11a1ab34c

tests/test-install-previous-keystone.yml

@@ -28,7 +28,7 @@
       vhost_name: "{{ keystone_rabbitmq_vhost }}"
       user_name: "{{ keystone_rabbitmq_userid }}"
       user_password: "{{ keystone_rabbitmq_password }}"
-      when: "{{ groups['rabbitmq_all'] is defined }}"
+      when: groups['rabbitmq_all'] is defined
     - include: common/create-grant-db.yml
       db_name: "{{ keystone_galera_database }}"
       db_password: "{{ keystone_container_mysql_password }}"