Log RemoteExceptions from RollbackManager.

It is entirely possible to get a RemoteException from RollbackManager,
even if it is in the same process. Remove the comments that suggest
otherwise and log the failures instead.

Bug: 136461171
Test: atest CtsRollbackManagerHostTestCases:com.android.cts.rollback.host.RollbackManagerHostTest#testApexAndApkStagedRollback
Change-Id: I8e7936ada5c19b53be4e3e8dc5ad7165d216d8ac