pptp: Accept packet with seq zero

Initialize the PPTP "seq received" value to 0xffffffff, so we don't
ignore packets with seq zero.

Signed-off-by: Bradley Peterson <despite@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index c1c9293..df884dd 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -585,8 +585,8 @@
 	po = pppox_sk(sk);
 	opt = &po->proto.pptp;
 
-	opt->seq_sent = 0; opt->seq_recv = 0;
-	opt->ack_recv = 0; opt->ack_sent = 0;
+	opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
+	opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
 
 	error = 0;
 out: