Upgrade libnet from 1.22 to 1.22_02

This is the latest (development) release on CPAN. It will shortly be
superseded by 1.23.

Note that Makefile.PL is only customized -- not excluded as well! Two
customized test files (actually, one changed and one added) which blead
had (but were not noted in the Maintainers.pl file!) are incorporated in
this release.

Also, change the UPSTREAM status from undef to 'blead' to reflect the fact
that GBARR is no longer actively maintaining libnet and for the immediate
future new CPAN releases are only likely to be rolled to keep in sync with
changes in blead, plus occasional simple patches from the CPAN RT queue.