Fix unneeded "Failed to get arguments" when run `gir --help`
Fix unneeded "Failed to get arguments" when run `gir --help`

Error already contained "Unknown flags" if needed

gtk-rs/gir,GuillaumeGomez/gir,GuillaumeGomez/gir,gtk-rs/gir,EPashkin/gir,GuillaumeGomez/gir,EPashkin/gir,gtk-rs/gir