[SK_BUFF]: Adjust the zeroing up to tail in __alloc_skb too

I did it just in alloc_skb_from_cache, forgot __alloc_skb, fixed now.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -164,7 +164,10 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	if (!data)
 		goto nodata;
 
-	memset(skb, 0, offsetof(struct sk_buff, truesize));
+	/*
+	 * See comment in sk_buff definition, just before the 'tail' member
+	 */
+	memset(skb, 0, offsetof(struct sk_buff, tail));
 	skb->truesize = size + sizeof(struct sk_buff);
 	atomic_set(&skb->users, 1);
 	skb->head = data;