Fix NPE in PackageManagerService.

Check that each package from the setting has
a parsed pkg before we attempt to perform dex-opt
on it. If it doesn't have a parsed package, adjust
the ABI in the settings, but don't perform dexopt.
It will be dexopted later if it's still active
based on the setting.

bug: 15081286

Change-Id: Ifb6d1d5efdc9c59b251731972afa951ad930d05c