Add explicit "fpm" version for now so our package build works like it's ...

...supposed to.

This is a stop-gap until I can fix what broke in 1.0.1 (which I'll work on right after I finish typing this).  Regardless, having an explicit version on our "gem install" here is a very good idea and will stay (just like we're explicit about s3cmd because we need very specific features from it).