base

Use Libcore.os.stat instead of FileUtils

PackageManagerService just needed to know the owner for this file, so
just use stat instead so we can remove the old JNI code.

This is the last user of FileUtils#getPermissions so just remove the
FileUtils method as well.

Change-Id: I953057cd6b9de4410f33b6f22e4bddff02fe2988