HADOOP-16344. Make DurationInfo public unstable.

Second attempt: imports fixed up.

Contributed by Huan-Ping Su and Kai Xie.

Change-Id: Ib2a85dd4b2d12b840692cc854cc53ddb3bdde7d5

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/DurationInfo.java

@@ -20,8 +20,8 @@ package org.apache.hadoop.util;
 
 import org.slf4j.Logger;
 
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.classification.InterfaceAudience.Public;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
 
 /**
  * A duration with logging of final state at info or debug
@@ -29,8 +29,8 @@ import org.apache.hadoop.classification.InterfaceStability;
  * This allows it to be used in a try-with-resources clause, and have the
  * duration automatically logged.
  */
-@InterfaceAudience.Private
-@InterfaceStability.Unstable
+@Public
+@Unstable
 public class DurationInfo extends OperationDuration
     implements AutoCloseable {
   private final String text;