rem: hash_uninit(void *_hash_table)
add: hash_uninit(struct hash_table *table)
context: hash_uninit(void *_hash_table){	struct hash_table *t = (struct hash_table *)_hash_table;#if 0	if(t->num_elems > 0) {		return -1;	}#endif	free(t->table);	free(t);	return 0;}