Avoid creating a useless prototype for the search ordering form

There is no JS code reading the prototype to add elements in the
collection. The UI hides the fields and builds links separately.

src/Packagist/WebBundle/Form/Type/SearchQueryType.php

@@ -27,7 +27,8 @@ class SearchQueryType extends AbstractType
         $builder->add('orderBys', 'collection', array(
             'type' => new OrderByType(),
             'allow_add' => true,
-            'allow_delete' => true
+            'allow_delete' => true,
+            'prototype' => false,
         ));
     }