HDFS-13529. Fix default trash policy emptier trigger time correctly. Contributed by He Xiaoqiao.

Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>
(cherry picked from commit f86de6f76a3079c2655df9b242fc968edfb17b9d)

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

@@ -271,9 +271,9 @@ public class TrashPolicyDefault extends TrashPolicy {
     public void run() {
       if (emptierInterval == 0)
         return;                                   // trash disabled
-      long now = Time.now();
-      long end;
+      long now, end;
       while (true) {
+        now = Time.now();
         end = ceiling(now, emptierInterval);
         try {                                     // sleep for interval
           Thread.sleep(end - now);