Travis workaround

Ha - I'm smart. Since [the Travis hook](https://github.com/mitchellh/vagrant-rackspace/issues/47) isn't enabled for mitchellh/vagrant-rackspace, we can setup a PR from that fork to this one.

This PR will keep building every time something is merged to mitchellh:master. So we won't have builds for PRs, but we'll at least have travis running *after* the PR is merged.