Unmount bind-mounts on top of /data before unmounting /data

Test: adb shell setprop sys.init.userdata_remount.force_umount_f2fs 1
Test: adb shell /system/bin/vdc checkpoint startCheckpoint 1
Test: adb reboot userspace
Bug: 135984674
Bug: 143970043
Change-Id: Icd7f3ad1c42d9b21bf4eacf1dec60355c9883254
1 file changed