Small refactoring to apps list.

- Fixes issue with fading in app icons when items are added/removed
- Reduces number of expensive calls when drawing sections and the scrollbar
- Removes fake section AppInfos in the adapters

src/com/android/launcher3/BubbleTextView.java

@@ -388,11 +388,6 @@ public class BubbleTextView extends TextView {
         }
     }
 
-    @Override
-    protected boolean onSetAlpha(int alpha) {
-        return true;
-    }
-
     @Override
     public void cancelLongPress() {
         super.cancelLongPress();