Fix for failing test on node 0.10
Fix for failing test on node 0.10

After merging #593, tests against node 0.10 started failing with

```
util.js:556
  ctor.prototype = Object.create(superCtor.prototype, {
                          ^
TypeError: Object prototype may only be an Object or null
```

crashlytics/statsd,etsy/statsd,etsy/statsd,bmhatfield/statsd,bmhatfield/statsd,etsy/statsd,crashlytics/statsd,bmhatfield/statsd,crashlytics/statsd