RFC5722 Section 4 was amended by Errata 3089

Our implementation did the right thing anyway...
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>