Errors are not captured for putFile() requests

[oliverlloyd]

The code below should fail, I am sending invalid credentials but e is null and I am forced to read the res object to get the statusCode value which, incidentally, is correctly set as 403.

var client = knox.createClient({
            key: 'ABCGARBAGE'
          , secret: 'UTTERLYSHOULDNEVERWORK'
          , bucket: 'mybucket'
});

var putReq = client.putFile(source, dest, function(e, res){
                console.log(e)...

[domenic]

Knox does not actually handle HTTP errors. From its perspective, the request completed successfully; you would get e !== null if there were some kind of network problem, for example. You'll notice the first few examples in the readme check the status code against 200 as well.

That said, I agree this is not as user-friendly as it could be. See #59. I think I'll close both this and that one and open a new, better-named bug to track this issue.