Fix problem with commit from 8.12.17 / Store.php: appendToStore.php stopped working.

extension/qfq/qfq/store/Store.php

@@ -875,7 +875,7 @@ class Store {
      */
     public static function appendToStore($storeName, $values) {
 
-        if (empty($value) || !is_array($value)) {
+        if (empty($values) || !is_array($values)) {
             return;
         }