[PKT_SCHED]: HTB: Drop packet when direct queue is full

htb_enqueue(): Free skb and return NET_XMIT_DROP if a packet is
destined for the direct_queue but the direct_queue is full. (Before
this: erroneously returned NET_XMIT_SUCCESS even though the packet was
not enqueued)
Signed-off-by: Asim Shankar <asimshankar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_htb.c

@@ -717,6 +717,10 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	if (q->direct_queue.qlen < q->direct_qlen) {
 	    __skb_queue_tail(&q->direct_queue, skb);
 	    q->direct_pkts++;
+	} else {
+	    kfree_skb(skb);
+	    sch->qstats.drops++;
+	    return NET_XMIT_DROP;
 	}
 #ifdef CONFIG_NET_CLS_ACT
     } else if (!cl) {