ListFile warns of unable to delete old state when there was none

Now with the inclusion of NIFI-259 ListFile we have state management. ListFile has logic to migrate old state. When you add a new ListFile processor to the graph and start pulling data it warns (see attached) that it migrated state (but there was none) but that it could delete the old state file (but there was none). It should only say this if it actually migrated state and actually had trouble deleting an old existing file.