Use non-deprecated HeaderItem constructor.

b/17455376

Change-Id: I9fff76367ffe1f96642a39962e51c935cf39d10b
diff --git a/samples/SupportLeanbackDemos/src/com/example/android/leanback/DetailsFragment.java b/samples/SupportLeanbackDemos/src/com/example/android/leanback/DetailsFragment.java
index 5354efd..bc88e21 100644
--- a/samples/SupportLeanbackDemos/src/com/example/android/leanback/DetailsFragment.java
+++ b/samples/SupportLeanbackDemos/src/com/example/android/leanback/DetailsFragment.java
@@ -163,7 +163,7 @@
                     listRowAdapter.add(new PhotoItem("This is a test", R.drawable.gallery_photo_2));
                     listRowAdapter.add(new PhotoItem("Android TV", R.drawable.gallery_photo_3));
                     listRowAdapter.add(new PhotoItem("Leanback", R.drawable.gallery_photo_4));
-                    HeaderItem header = new HeaderItem(i, "Row " + i, null);
+                    HeaderItem header = new HeaderItem(i, "Row " + i);
                     mRowsAdapter.add(new ListRow(header, listRowAdapter));
                 }
                 if (TEST_ENTRANCE_TRANSITION) {