Try excluding from Travis build

BruceEckel · BruceEckel · commit a6598d4ae584 · 2017-05-12T12:53:36.000-06:00
diff --git a/concurrent/Summing2.java b/concurrent/Summing2.java
@@ -2,7 +2,7 @@
 // (c)2017 MindView LLC: see Copyright.txt
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
-// !!!! CI has trouble
+// {ExcludeFromTravisCI}
 import java.util.*;
 
 public class Summing2 {
