Fix drag handler position calculation

[Helco]

I noticed, that if you set the drag handler to a view whose parent is not the view generated by the adapter, the dragging-enabled area is not calculated right.

To test this replace the content of testitem.xml (DragNDropListApp) with

<TextView
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/handler"
        android:layout_width="60px"
        android:layout_height="60px"
        android:src="@android:drawable/btn_star_big_on"
        android:layout_marginLeft="8px"
        />
</FrameLayout>