Fixed grant for icinga user

The ::icinga2::feature::idomysql class by defaults connect to 127.0.0.1.  The icinga mysql user grants must match.

README.md

@@ -162,7 +162,7 @@ include ::mysql::server
 mysql::db { 'icinga2':
   user     => 'icinga2',
   password => 'supersecret',
-  host     => 'localhost',
+  host     => '127.0.0.1',
   grant    => ['SELECT', 'INSERT', 'UPDATE', 'DELETE', 'DROP', 'CREATE VIEW', 'CREATE', 'INDEX', 'EXECUTE', 'ALTER'],
 }