Bump b2d to my v0.5.4-2-alpha

All I did to b2d was change some urls in mitchellh's b2d vagrant box. See commits on my fork; [a43ae34](https://github.com/username724/boot2docker-vagrant-box/commit/a43ae3406805324d9aa9988bc3bbde20bb8c2ae7) and [1117eb6](https://github.com/username724/boot2docker-vagrant-box/commit/1117eb6ff2e45e4b1c33d16c008695718f19c227) for the changes.

No idea what version to call this fork of dvm.