copy first level apk dir on movePackage

The goal is to make sure the code path still has two levels after the
move, on the target storage.

Test: manual as follows:
$ adb install ~/Downloads/yelp.apk
$ adb shell
walleye:/ # su
walleye:/ # sm set-virtual-disk true
walleye:/ # sm list-disks
disk:7,224
walleye:/ # sm partition disk:7,224 private
walleye:/ # sm list-volumes
private mounted null
private:7,226 mounted ea386596-0d69-4cd7-87f8-2d77ced59f0c
emulated;0 mounted null
emulated:7,226;0 unmounted null
walleye:/ # pm move-package com.yelp.android ea386596-0d69-4cd7-87f8-2d77ced59f0c
Success

Example log:
PackageManager: Update package com.yelp.android code path from /data/app/~~LKNWa_moIm9tFw5KY5E7ZA==/com.yelp.android-VgweFDciQH9cPQLnkooiMA== to /mnt/expand/ea386596-0d69-4cd7-87f8-2d77ced59f0c/app/~~LKNWa_moIm9tFw5KY5E7ZA==/com.yelp.android-VgweFDciQH9cPQLnkooiMA==

BUG: b/148844589 b/148237378
Change-Id: I46109a7befa8971a05049b4f495ca0d73e244a0b