Fix GTK dialog replacement of $filename$
Fix GTK dialog replacement of $filename$

When using GTK dialogs on a *nix system, the dialog box was displaying
"Overwrite '$filename$'?" instead of replacing '$filename$' with an
actual file name.  This ammends that to be in league with out the
"native" LibreOffice dialogs do it.

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core