update timestamps on pull-to-refresh even when no new statuses are fetched (#1393)

app/src/main/java/com/keylesspalace/tusky/fragment/NotificationsFragment.java

@@ -995,6 +995,7 @@ public class NotificationsFragment extends SFragment implements
 
     private void update(@Nullable List<Notification> newNotifications, @Nullable String fromId) {
         if (ListUtils.isEmpty(newNotifications)) {
+            updateAdapter();
             return;
         }
         if (fromId != null) {

app/src/main/java/com/keylesspalace/tusky/fragment/TimelineFragment.java

@@ -1116,6 +1116,7 @@ public class TimelineFragment extends SFragment implements
 
     private void updateStatuses(List<Either<Placeholder, Status>> newStatuses, boolean fullFetch) {
         if (ListUtils.isEmpty(newStatuses)) {
+            updateAdapter();
             return;
         }