fix golint issues, exported doc (#451)

rest/handler/timeouthandler.go

@@ -7,12 +7,13 @@ import (
 
 const reason = "Request Timeout"
 
+// TimeoutHandler returns the handler with given timeout.
 func TimeoutHandler(duration time.Duration) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		if duration > 0 {
 			return http.TimeoutHandler(next, duration, reason)
-		} else {
-			return next
 		}
+
+		return next
 	}
 }