Commit rollbacks by ID, not by RollbackInfo.

To make it clear that the system only pays attention to the provided
rollback ID when committing a rollback.

Also, rename executeRollback to commitRollback in IRollbackManager.aidl,
now that we are touching the code anyway.

Bug: 112431924
Test: atest RollbackTest
Change-Id: I315e75c39019536fb2f090a0c84ed4cf7c03ce8c
7 files changed