Rescan apps after restore and re-publish manifest shortcuts

Originally when I wrote backup & restore for ShortcutManager,
there was no manifest shortcuts, so there was no need to
handle preintalled apps specially.

However, now we have manifest shortcuts, which are published
when the user is unlocked, by the time restore happens preinstalled
apps may already have manifest shortcuts, which will be overwritten
by the restored shortcuts.

So we need to re-publish manifest shortcuts after restore.

Bug 30746028

Change-Id: I6afbae7790c9ed38483637f33c381ecb6f854677