not working on OS X 10.6.8, vagrant 1.2.2

I copied the vagrant file into /etc/bash_completion.d/vagrant and re-sourced [my ~/.bashrc](https://github.com/deanmalmgren/config/blob/master/bashrc) but the tab completion doesn't seem to be working for me. Is this a problem with my .bashrc, an issue with OS X, or something else altogether?

Happy to help debug but I don't really know where to start. I'd love to use this package as our vagrant VM names are getting a little annoying to have to type all the time...