[ticket/14262] Move convertor to controller

PHPBB3-14262

phpBB/phpbb/install/helper/iohandler/iohandler_base.php

@@ -169,6 +169,14 @@ abstract class iohandler_base implements iohandler_interface
 		$this->current_task_progress = $this->task_progress_count;
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function generate_form_render_data($title, $form)
+	{
+		return '';
+	}
+
 	/**
 	 * Localize message.
 	 *