Add selinux rules for userspace reboot related properties

By default sys.init.userspace_reboot.* properties are internal to
/system partition. Only exception is
sys.init.userspace_reboot.in_progress which signals to all native
services (including vendor ones) that userspace reboot is happening,
hence it should be a system_public_prop.

Only init should be allowed to set userspace reboot related properties.

Bug: 135984674
Test: builds
Test: adb reboot userspace
Change-Id: Ibb04965be2d5bf6e81b34569aaaa1014ff61e0d3
7 files changed