Merge "vold: add getUnlockedUsers() method to Binder interface" am: 5e5819a761 am: ffcb495f2c am: b22fa25e7b

Original change: https://android-review.googlesource.com/c/platform/system/vold/+/1674805

Change-Id: I46101eff7eaa690af8c3dc53442ba05d9a30bb8b