tcp: Fix syncookies sysctl default.

Unintentionally the default was changed to zero, fix
that.

Fixes: 12ed8244ed ("ipv4: Namespaceify tcp syncookies sysctl knob")
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_ipv4.c

@@ -2389,7 +2389,7 @@ static int __net_init tcp_sk_init(struct net *net)
 
 	net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
 	net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
-	net->ipv4.sysctl_tcp_syncookies = 0;
+	net->ipv4.sysctl_tcp_syncookies = 1;
 	net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
 	net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
 	net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;