AbstractException.php: fix new problem after exception output has been reordered

extension/qfq/qfq/exceptions/AbstractException.php

@@ -68,6 +68,7 @@ class AbstractException extends \Exception {
         $arrShow = $this->messageArray;
         $htmlDebug = '';
         $arrDebugShow = array();
+        $arrForm = [];
 
         try {
             // In a very early stage, it might be possible that Store can't be initialized: take care not to use it.