Merge "Reboot sequence: Unmount active apexes before unmounting /data" am:...

Merge "Reboot sequence: Unmount active apexes before unmounting /data" am: b2551953 am: d60f0708 am: 64697dcd am: 97870085

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1327913

Change-Id: I7b270f5aa95f686ced50d862b02f91f69d22d01b