YARN-7380. Fix findbugs warning in timeline service on branch-2 (Vrushali C via Varun Saxena).

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice-hbase/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/common/ColumnHelper.java

@@ -258,7 +258,7 @@ public class ColumnHelper<T> {
               for (Entry<Long, byte[]> cell : cells.entrySet()) {
                 V value =
                     (V) converter.decodeValue(cell.getValue());
-                Long ts = supplementTs ? TimestampGenerator.
+                long ts = supplementTs ? TimestampGenerator.
                     getTruncatedTimestamp(cell.getKey()) : cell.getKey();
                 cellResults.put(ts, value);
               }