Fix groupBy/timeseries test, follow up to #705.

processing/src/test/java/io/druid/query/groupby/GroupByTimeseriesQueryRunnerTest.java

@@ -150,6 +150,13 @@ public class GroupByTimeseriesQueryRunnerTest extends TimeseriesQueryRunnerTest
     // fill anything in.
   }
 
+  @Override
+  public void testTimeseriesQueryZeroFilling()
+  {
+    // Skip this test because the timeseries test expects skipped hours to be filled in, but group by doesn't
+    // fill anything in.
+  }
+
   @Override
   public void testTimeseriesWithNonExistentFilter()
   {