Merge changes I6a4c3d9b,Ia5cdb797,I946eb605,Ieff3f6ea

* changes:
  init: overlay: allow fs_mgr_overlayfs_required_devices to report partitions
  fastboot: call fs_mgr_overlayfs_teardown() in UpdateSuper
  fs_mgr: overlay: disable overrides in recovery or fastbootd.
  fs_mgr: overlay: umount scratch more aggressively