[ticket/15274] Allow "custom" migrations to use parameters

Add the possibility to have custom migrations with parameters,
allowing the use of a single function for several uses.

PHPBB3-15274

phpBB/phpbb/db/migrator.php

@@ -784,7 +784,7 @@ class migrator
 				{
 					return array(
 						$parameters[0],
-						array($last_result),
+						isset($parameters[1]) ? array_merge($parameters[1], array($last_result)) : array($last_result),
 					);
 				}
 			break;