Fix traceroute applet on the FreeBSD

This patch addressing 2 issues:

1. Replacing source/dest with uh_sport/uh_dport. It seems that uh_* members are
   defined on both Linux and BSD, so no #ifdef here
2. Use SOL_IPV6 instead of SOL_RAW on the FreeBSD to fix IPV6_CHECKSUM setsockopt

Signed-off-by: Alex Samorukov <samm@os2.kiev.ua>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed