example/convenience-repo.js errors

i get this error when running `example/convenience-repo.js`:

```
node: /usr/include/nodejs/node_object_wrap.h:51: static T* node::ObjectWrap::Unwrap(v8::Handle<v8::Object>) [with T = GitOid]: Assertion `handle->InternalFieldCount() > 0' failed.
```

`node --version
v0.4.6`
