Merge "Improve logging for why a staged session was reverted" am: 55103afd...

Merge "Improve logging for why a staged session was reverted" am: 55103afd am: afb34c51 am: 8fd3ac3d

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1486201

Change-Id: I6c8c567ea1e636488466acc15d1405ce422a4aae