Upgrade libnet from 1.22_02 to 1.23

Changed my mind over the UPSTREAM status too: 'cpan' is probably better
after all. As long as someone (currently me) is responsive in rolling new
CPAN releases then any patches from core can safely go to rt.cpan.org
without getting stuck on a pile for a long time. Meanwhile, other patches
sent to rt.cpan.org may also get applied, and hopefully one day a more
active maintainer may be found. This also saves having to move it from
cpan/ to dist/.
Upgrade IO::Compress::* and Compress::Raw::* from 2.061 to 2.062
Upgrade Time::Piece from 1.21 to 1.22
Update t/porting/customized.dat for cpan/libnet/Makefile.PL