Unmount public volume if FUSE mount fails am: f71707916f am: c1f45db6e1 am: 3875f982dc am: 6343f2dc12

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/vold/+/11900947

Change-Id: Iabbd9276f5c2ef88fc4c84a82f43ceabb9f83568