Update fatpacked CPAN::Perl::Releases

* This avoids HTTP access to http://search.cpan.org/dist/perl-* for newer perl versions.
* Combine with `$ENV{PERL_BUILD_CPAN_MIRROR}` to completely avoid  HTTP accesses to http://search.cpan.org/

```sh
PERL_BUILD_CPAN_MIRROR="http://ftp.nara.wide.ad.jp/pub/CPAN" perl-build 5.20.0 /opt/perl-5.20/
```