Cat the bundler setup file.

Travis is failing our builds due to a missing constant in this file but locally the constant isn't in my generated setup file.
Downgrade bundler until the travis VMs have a new bundler release.
Fix the way we uninstall bundler.

Based on:

https://twitter.com/mpapis/status/311141006621933570
https://twitter.com/mpapis/status/311153169264701440