Invalid JSON in metadata.json

This makes Librarian unhappy.

```
/home/stbenjam/.rvm/rubies/ruby-2.0.0-p576/lib/ruby/2.0.0/json/common.rb:155:in `parse': 399: unexpected token at '] (JSON::ParserError)
    }
  ],
  "dependencies": [
    {"name":"puppetlabs/apt","version_requirement":">= 1.0.0"},
    {"name":"puppetlabs/stdlib","version_requirement":">= 2.2.0"}
  ]
}
'
	from /home/stbenjam/.rvm/rubies/ruby-2.0.0-p576/lib/ruby/2.0.0/json/common.rb:155:in `parse'
```