Added toString to ContainerToken. Contributed by Jason Lowe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1310537 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/impl/pb/ContainerTokenPBImpl.java

@@ -155,4 +155,12 @@ public class ContainerTokenPBImpl extends ProtoBase<ContainerTokenProto> impleme
     builder.setService((service));
   }
 
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("ContainerToken { ");
+    sb.append("kind: ").append(getKind()).append(", ");
+    sb.append("service: ").append(getService()).append(" }");
+    return sb.toString();
+  }
 }