fixed: poor handling of error responses when getting auth header
fixed: poor handling of error responses when getting auth header

enketo/enketo-express,onaio/enketo-express,kobotoolbox/enketo-express,enketo/enketo-express,OpenClinica/enketo-express-oc,kobotoolbox/enketo-express,kobotoolbox/enketo-express,OpenClinica/enketo-express-oc,onaio/enketo-express,onaio/enketo-express,kobotoolbox/enketo-express,OpenClinica/enketo-express-oc,enketo/enketo-express