quote password environment variable in case it contains shell metacharacters

roles/mailserver/handlers/main.yml

@@ -11,6 +11,5 @@
   service: name=tomcat6 state=restarted
 
 - name: import sql postfix
-  action: shell PGPASSWORD={{ mail_db_password }} psql -h localhost -d {{ mail_db_database }} -U {{ mail_db_username }} -f /etc/postfix/import.sql --set ON_ERROR_STOP=1
+  action: shell PGPASSWORD='{{ mail_db_password }}' psql -h localhost -d {{ mail_db_database }} -U {{ mail_db_username }} -f /etc/postfix/import.sql --set ON_ERROR_STOP=1
   notify: restart postfix
-