[Fix] Catch it

Fix for issue #232 and #261.

websocket-sharp/Net/EndPointListener.cs

@@ -244,6 +244,9 @@ namespace WebSocketSharp.Net
       try {
         sock = lsnr._socket.EndAccept (asyncResult);
       }
+      catch (SocketException) {
+        // TODO: Should log the error code when this class has a logging.
+      }
       catch (ObjectDisposedException) {
         return;
       }