Use upstart in user session mode for managing services in chroot

By running the upstart daemon in user session mode and setting a few
environment variables, upstart will start services successfully.  This
allows the user to simply install packages without doing anything
special or different than they would have to on a non-chroot install.

I don't know how to test the changes to the bin/linuxdeploy script so I just recorded there what *should* make the same changes I had to make to my Ubuntu Raring install to get upstart managing my services.  So this is more of a starting point but I do think it would be an improvement if merged and tested.