[PKT_SCHED] sch_htb: Use hlist_del_init().

Otherwise we can hit paths that (legally) do multiple deletes on the
same node and OOPS with the HLIST poison values there instead of
NULL.

Signed-off-by: David S. Miller <[e-mail]>

net/sched/sch_htb.c

···
 						  struct htb_class, sibling));
 
 	/* note: this delete may happen twice (see htb_delete) */
-	if (!hlist_unhashed(&cl->hlist))
-		hlist_del(&cl->hlist);
+	hlist_del_init(&cl->hlist);
 	list_del(&cl->sibling);
 
 	if (cl->prio_activity)
···
 	sch_tree_lock(sch);
 
 	/* delete from hash and active; remainder in destroy_class */
-	if (!hlist_unhashed(&cl->hlist))
-		hlist_del(&cl->hlist);
+	hlist_del_init(&cl->hlist);
 
 	if (cl->prio_activity)
 		htb_deactivate(q, cl);