Merge "Abandon other staged sessions when a rollback is staged." into sc-dev am: 79bbe49b am: 1979201d am: c14ebd27

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15132975

Change-Id: I29c49308291e2943ccb94c5d8cd85da78ea00363