Dont try to parse JSON if the statusCode is 204 (No Content)

I dont think that wreck should try to parse json when the status code is 204 no content.
We keep getting '''Unexpected end of line''' and other errors. 

I have created a test and updated the code not to parse JSON if the statusCode is 204.

If there is any problem with it, just let me know :)


  
Might be an issue with the github  source viewer, but looks like this needs 4 spaces