Fix golint

recent additions to golint mean that a number of files cause the
build to start failing if they are edited (we only run against changed
files)

This fixes all the errors in the repo so things don't unexpectedly start
failing for people making PRs

configuration.go

@@ -234,10 +234,10 @@ func (certs *Certificates) CreateTLSConfig() (*tls.Config, error) {
 			if errKey == nil {
 				isAPath = true
 			} else {
-				return nil, fmt.Errorf("Bad TLS Certificate KeyFile format. Expected a path.")
+				return nil, fmt.Errorf("bad TLS Certificate KeyFile format, expected a path")
 			}
 		} else if errKey == nil {
-			return nil, fmt.Errorf("Bad TLS Certificate KeyFile format. Expected a path.")
+			return nil, fmt.Errorf("bad TLS Certificate KeyFile format, expected a path")
 		}
 
 		cert := tls.Certificate{}