#629 Settings TBlobField.asString showing empty value in TDBMemo

[Nick Nevzorov]

Hi

Need some changes in ZDbcResultSet.pas

Because FOwner.SetUpdated(True) after FVarLenDataRef.VarLenData := nil generetes TDBMemo.DataChange event and TBlobField.asString is empty in this time

In exmaple try click on button. Method sets field value as '123', but DBMemo is clear

P.S. https://github.com/NickNevzorov/zeoslib/pull/10