[NETFILTER]: tcp conntrack: fix IP_CT_TCP_FLAG_CLOSE_INIT value

IP_CT_TCP_FLAG_CLOSE_INIT is a flag and should have a value of 0x4 instead
of 0x3, which is IP_CT_TCP_FLAG_WINDOW_SCALE | IP_CT_TCP_FLAG_SACK_PERM.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>