access logger: read status code from HTTPError, if returned by c.Next()

[kmsb12]

The access logger takes the status code, which is being logged, from the LogResponseWriter. If the c.Next() handler does not use WriteHeader, but instead returns a HTTPError, the access logger will log the request with a 200 OK status. (e.g. if serving static files and the requested file does not exist, status code in log will be 200 and not the returned 404)
To fix this, we need to check the error object returned by c.Next() and use its status code if available.

[coveralls]

Coverage remained the same at 95.089% when pulling 1a17ad4 on studio-b12:master into 8c1099a on go-ozzo:master.

[qiangxue]

You should use fault.Recovery middleware after the access logger. It will correctly handle the error and set response status code.

[kmsb12]

Thanks for your quick reply. With fault.Recovery it's working fine.