500 error attempting to yank a release

```
~/rust/rust-openssl ❯ cargo yank --vers 1.0.0
    Updating registry `https://github.com/rust-lang/crates.io-index`
        Yank openssl:1.0.0
failed to yank: failed to get a 200 OK response: Response {500, connection: keep-alive, content-length: 30, date: Sun, 23 Nov 2014 07:04:03 GMT, server: nginx, via: 1.1 vegur, Error 404: Not Found
Not Found]
```
