CVE-2013-6401: Change hash function, randomize hashes

Thanks to Florian Weimer and Eric Sesterhenn for reporting, reviewing
and testing.
void *json_object_iter_next(json_t *json, void *iter)
{
    json_object_t *object;

    if(!json_is_object(json) || iter == NULL)
        return NULL;

    object = json_to_object(json);
    return hashtable_iter_next(&object->hashtable, iter);
}

void *json_object_iter_next(json_t *json, void *iter)
{
    json_object_t *object;

    if(!json_is_object(json) || iter == NULL)
        return NULL;

    object = json_to_object(json);
    return hashtable_iter_next(&object->hashtable, iter);
}
