ListView eill always show dividers below items if all items in the adapter are enabled.

It seems like it should not show a divider on the last item when there are headers
OR infer not all items enabled when there are headers, but it doesn't.

Fixes b/5517092 extra divider line between last label and next header in label list

Change-Id: Ib0f0361e672edcc36c973166c062b67e61ec59c4

src/com/android/email/activity/MailboxFragmentAdapter.java

@@ -191,6 +191,13 @@ class MailboxFragmentAdapter extends CursorAdapter {
         return !isHeader(position);
     }
 
+    // The LabelList has headers which are not
+    // enabled.
+    @Override
+    public boolean areAllItemsEnabled() {
+        return false;
+    }
+
     @Override
     public void bindView(View view, Context context, Cursor cursor) {
         if (view instanceof MailboxListItem) {