tcp: factorize sk_txhash init

Neal suggested to move sk_txhash init into tcp_create_openreq_child(),
called both from IPv4 and IPv6.

This opportunity was missed in commit 58d607d3e52f ("tcp: provide
skb->hash to synack packets")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 10933d0..85830bb 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -471,6 +471,7 @@
 		tcp_enable_early_retrans(newtp);
 		newtp->tlp_high_seq = 0;
 		newtp->lsndtime = treq->snt_synack.stamp_jiffies;
+		newsk->sk_txhash = treq->txhash;
 		newtp->last_oow_ack_time = 0;
 		newtp->total_retrans = req->num_retrans;