toolbox: Add levelFromUid categorization support to restorecon

This is necessary for the app data relabeling on migrated devices
to include the proper app context. Freshly installed apps get this
done automagically, as do newly created files.

Change-Id: If7421dac01c6ae8bd78e66f71e69298ed850a7ab
ueventd: restorecon sysfs files

Allow cpufreq governor tuning files to be labelled correctly after
switching governor.

Change-Id: I3e0fd310aaacbb4e647e42597d38040774257955

Conflicts:
	init/devices.c