New JSON must be massaged

I wasted 2 hours of my life because 'sudo fauxhai > /tmp/fauxhai.json' wrote out a JSON file that included the initial line:

```
[2013-10-10T10:43:19-04:00] WARN: unable to detect ip6address
```

:(

Since this clearly should have gone to stderr (I've opened an issue in Opscode JIRA for this re: ohai), and not stdout into my file, it silently produces an invalid JSON file.

The updated instructions are at least a *little* better now as they indicate you should pipe to `sed '/ WARN: /D'`