|The stupid question is the question not asked
The extra output is being generated by the CPAN module itself. I checked out the code on mine and I don't see any conditionals or anything that could be passed to supress that output. So, the simple answer is to grep for what you want or use perlmodver.pl CPAN | tail +5 because I don't think there's much you can do from the perl side that doesn't require putting more effort into it than it's worth.
Therapy is expensive. Popping bubble wrap is cheap. You choose.