ATLAS-3601 :- No LABEL_DELETE event is audited when last label is deleted.

repository/src/main/java/org/apache/atlas/repository/audit/AbstractStorageBasedAuditRepository.java

@@ -158,7 +158,7 @@ public abstract class AbstractStorageBasedAuditRepository implements Service, En
   protected byte[] getKey(String id, Long ts, int index) {
     assert id != null  : "entity id can't be null";
     assert ts != null  : "timestamp can't be null";
-    String keyStr = id + FIELD_SEPARATOR + ts + FIELD_SEPARATOR + index;
+    String keyStr = id + FIELD_SEPARATOR + ts + FIELD_SEPARATOR + index + FIELD_SEPARATOR + System.currentTimeMillis();
     return Bytes.toBytes(keyStr);
   }