Wrong update count

[fsuter]

The StoreDataStep does not report properly on the number of records updated. It counts the number of records which are prepared for update and then sent to the DataHandler, but if the data is actually unchanged the DataHandler will perform no update. Hence the update count is not correct. However in order not to scare users into thinking that nothing happened, External Import should report about unchanged records, in order to confirm that all records were indeed handled, even if there was nothing to do.