This isn't exactly an answer to your question, but I needed to use cpan2rpm a couple years ago and got pretty frustrated with it's limitations (doesn't work well with Module::Build modules was a big one). I ended up rewriting it (mine is called cpantorpm). It handles quite a few cases that cpan2rpm doesn't. It is NOT a drop-in replacement, but it may work where cpan2rpm doesn't (since I'm not a Jenkins user, I can't really say).

Read about it here:CPANtoRPM