PhysicalUndoOperation is a compensation operation that rolls back the change of
an Undo-able operation. A PhysicalUndoOperation itself is not undo-able, i.e,
it is loggable but not undoable.
Apply the undo operation, in this implementation of the
RawStore, it can only call the undoMe method of undoOp
Parameters: xact - the Transaction that is doing the rollback Parameters: instant - the log instant of this undo operation Parameters: in - optional data exception: IOException - Can be thrown by any of the methods of InputStream. exception: StandardException - Standard Cloudscape policy.