check the mysql 5.6 experiment is installed or not

playbooks/roles/mysql/tasks/main.yml

 ---
 - name: Look for mysql 5.6
-  shell: dpkg -L mysql-server-5.6
+  shell: "dpkg -s mysql-server"
   ignore_errors: yes
   register: mysql_56_installed
- 
+  changed_when: no
+
+- fail:
+    msg: "You have already installed the experimental MySQL 5.6 repo, Please first remove that"
+  when: "'5.6.14' in  mysql_56_installed.stdout"
+
 - include: mysql.yml
   when: mysql_56_installed.rc == 1
\ No newline at end of file

playbooks/roles/mysql/tasks/mysql.yml

@@ -14,7 +14,6 @@
   apt: 
     name: "{{ item }}" 
     install_recommends: yes
-    update_cache: yes
     state: present
   with_items: mysql_debian_pkgs