Incorrect Authentication Info raises unhandled exception 

Because we try to manipulate `response.exit_code = -1` before it has a value.

```
NoMethodError: undefined method `exit_code=' for nil:NilClass
	/Users/kallan/src/ridley/lib/ridley/host_connector/winrm/worker.rb:82:in `rescue in run'
	/Users/kallan/src/ridley/lib/ridley/host_connector/winrm/worker.rb:50:in `run'
```