girwriter: Don't write any custom attributes
girwriter: Don't write any custom attributes

Fixes https://gitlab.gnome.org/GNOME/vala/issues/608

frida/vala,GNOME/vala,frida/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala,frida/vala,GNOME/vala