ospfd: fix packet reception for FreeBSD 10.

* ospf_packet.c (ospf_recv_packet): FreeBSD, starting from version 10, will not
  subtract the IP header size from ip_len.

This is the patch from FreeBSD's ports/net/quagga/files/patch-ospfd__ospf_packet.c,
by Boris Kovalenko.
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index f8887c5..0705082 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -2121,7 +2121,7 @@
   
   ip_len = iph->ip_len;
   
-#if !defined(GNU_LINUX) && (OpenBSD < 200311)
+#if !defined(GNU_LINUX) && (OpenBSD < 200311) && (__FreeBSD_version < 1000000)
   /*
    * Kernel network code touches incoming IP header parameters,
    * before protocol specific processing.