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

Thanks to Florian Weimer and Eric Sesterhenn for reporting, reviewing
and testing.
void hashtable_close(hashtable_t *hashtable)
{
    hashtable_do_clear(hashtable);
    jsonp_free(hashtable->buckets);
}

void hashtable_close(hashtable_t *hashtable)
{
    hashtable_do_clear(hashtable);
    jsonp_free(hashtable->buckets);
}
