Fix a typo in ObjectEchoClientHandler

This fixes #510 in master

Signed-off-by: Cruz Julian Bishop <cruzjbishop@gmail.com>

example/src/main/java/io/netty/example/objectecho/ObjectEchoClientHandler.java

@@ -57,7 +57,7 @@ public class ObjectEchoClientHandler extends ChannelInboundMessageHandlerAdapter
 
     @Override
     public void messageReceived(ChannelHandlerContext ctx, List<Integer> msg) throws Exception {
-        // Echo back the received object to the client.
+        // Echo back the received object to the server.
         ctx.write(msg);
     }