Updated build/script/perl.rb for Dist::Zilla

It is common to create a Perl distribution using the Dist::Zilla helper,
which means keeping the package un-ready for release in version control
and only creating the release-ready version (with Makefile.PL or
Build.PL) when it actually gets shipped off to the CPAN.

For example:

https://metacpan.org/source/KAORU/App-highlight-0.09
https://github.com/kaoru/App-highlight

Added the steps to recognise that a repository has a dist.ini file and
that Dist::Zilla should therefore be used to install the dependencies
and to run the tests.
Merge pull request #95 from kaoru/perl-build-dist-zilla-fix

Updated build/script/perl.rb for Dist::Zilla