Fix bug where RemoteViews addView is backwards.

The index on where to add a child view was not being saved when writing
to a Parcel. This causes the index to default to 0 and resulted in views
always being added as the first view.

Now, persist this value to the Parcel and restore it.

Test: booted up on Nexus 6P, created notification with RemoteView, added
two views and verified views added in correct order.
Bug: 63177271

Change-Id: I94384e348b8a5168efe0601f382cdd2db6791fdb