@xiangli-cmu I looked at this but I couldn't figure out how to get some of the variables from [L171](https://github.com/coreos/etcd/pull/630/files#diff-1f8872a5d54402aa220c723deb16293cR171) within `internalCreate()` such as `n.ModifiedIndex` and `n.CreatedIndex`.

I didn't want to mess with the logic too much especially since the `internalCreate()` call from `Create()` doesn't need `prevNode`.