use bool filter on bare variable to address Ansible 2.8 deprecation warning

Signed-off-by: Jason Daly <[email protected]>

Author: deefour

tasks/main.yml

@@ -10,12 +10,12 @@
   tags: always
 
 - include: configure.yml
-  when: mysql_hardening_enabled
+  when: mysql_hardening_enabled | bool
   tags:
     - mysql_hardening
 
 - include: mysql_secure_installation.yml
-  when: mysql_hardening_enabled
+  when: mysql_hardening_enabled | bool
   tags:
     - mysql_hardening
     - mysql_secure_installation