[feature/module_services] Pass phpBB dbal driver to module uninstall method

portal/modules/portal_topposters.php

@@ -98,10 +98,8 @@ class portal_topposters_module extends \board3\portal\modules\module_base
 		return true;
 	}
 
-	public function uninstall($module_id)
+	public function uninstall($module_id, $db)
 	{
-		global $db;
-
 		$del_config = array(
 			'board3_topposters_' . $module_id,
 		);