Amend HADOOP-8408 per Daryn's post-commit feedback.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1341339 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFileSystem.java

@@ -236,7 +236,7 @@ public class ViewFileSystem extends FileSystem {
   
   @Override
   public String getCanonicalServiceName() {
-    return getUri().getHost();
+    return null;
   }
 
   @Override

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/viewfs/TestViewFileSystemDelegationTokenSupport.java

@@ -31,15 +31,15 @@ import org.junit.Test;
 /**
  * Test ViewFileSystem's support for having delegation tokens fetched and cached
  * for the file system.
+ * 
+ * Currently this class just ensures that getCanonicalServiceName() always
+ * returns <code>null</code> for ViewFileSystem instances.
  */
 public class TestViewFileSystemDelegationTokenSupport {
   
   private static final String MOUNT_TABLE_NAME = "vfs-cluster";
 
   /**
-   * Ensure that a canonical service name can be determined for ViewFileSystem
-   * instances configured with a non-default mount table name.
-   * 
    * Regression test for HADOOP-8408.
    */
   @Test
@@ -53,8 +53,7 @@ public class TestViewFileSystemDelegationTokenSupport {
         "://" + MOUNT_TABLE_NAME), conf);
     
     String serviceName = viewFs.getCanonicalServiceName();
-    assertNotNull(serviceName);
-    assertEquals(MOUNT_TABLE_NAME, serviceName);
+    assertNull(serviceName);
   }
   
   @Test