Allow init the ability to relabel recovery block devices. In the case
where we have recovery as a chain partition, due to its presence in
early mount node, init, in first stage itself would require relabel
permissions for the restorecon operation on recovery block device.

Bug: 73642793
Test: On bootup, recovery partition gets the appropriate se-label.
      Perform OTA on non-A/B device with recovery as chain partition,
      now the recovery partition gets upgraded successfully, now that
      it has the correct se-label.

Change-Id: I370c510320e78ab78c9c55573073415b4983d0f6