[Modify] Polish it

websocket-sharp/Server/HttpServer.cs

@@ -1310,17 +1310,8 @@ namespace WebSocketSharp.Server
           throw new InvalidOperationException (msg);
       }
 
-      if (_state == ServerState.Start) {
-        _log.Info ("The server has already started.");
-
-        return;
-      }
-
-      if (_state == ServerState.ShuttingDown) {
-        _log.Warn ("The server is shutting down.");
-
+      if (_state == ServerState.Start || _state == ServerState.ShuttingDown)
         return;
-      }
 
       start ();
     }