simplified a use statement

core/FrontController.php

@@ -16,7 +16,7 @@ use Piwik\Plugin\Controller;
 use Piwik\Plugin\Report;
 use Piwik\Plugin\Widgets;
 use Piwik\Session;
-use \Piwik\Plugins\CoreHome\Controller as CoreHomeController;
+use Piwik\Plugins\CoreHome\Controller as CoreHomeController;
 
 /**
  * This singleton dispatches requests to the appropriate plugin Controller.