[TCP]: Restore SKB socket owner setting in tcp_transmit_skb().

Revert 931731123a

We can't elide the skb_set_owner_w() here because things like certain
netfilter targets (such as owner MATCH) need a socket to be set on the
SKB for correct operation.

Thanks to Jan Engelhardt and other netfilter list members for
pointing this out.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/protocol.c

@@ -804,7 +804,7 @@ static inline int sctp_v4_xmit(struct sk_buff *skb,
 			  NIPQUAD(((struct rtable *)skb->dst)->rt_dst));
 
 	SCTP_INC_STATS(SCTP_MIB_OUTSCTPPACKS);
-	return ip_queue_xmit(skb, skb->sk, ipfragok);
+	return ip_queue_xmit(skb, ipfragok);
 }
 
 static struct sctp_af sctp_ipv4_specific;