Use CloseWithError(err) as per https://github.com/w3c/wptdashboard/pull/359#discussion_r161792453
Use CloseWithError(err) as per https://github.com/w3c/wptdashboard/pull/359#discussion_r161792453

GoogleChrome/wptdashboard,GoogleChrome/wptdashboard,GoogleChrome/wptdashboard