printing: Make GtkPrinter have a useful icon by default
printing: Make GtkPrinter have a useful icon by default

It causes complication elsewhere if gtk_printer_get_icon_name()
returns NULL initially. So make the icon name default to
"printer".

grubersjoe/adwaita,jigpu/gtk,davidgumberg/gtk,grubersjoe/adwaita,Lyude/gtk-,jigpu/gtk,jigpu/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,chergert/gtk,Adamovskiy/gtk,jadahl/gtk,Lyude/gtk-,Adamovskiy/gtk,chergert/gtk,Adamovskiy/gtk,jadahl/gtk,chergert/gtk,ahodesuka/gtk,jadahl/gtk,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,Adamovskiy/gtk,ahodesuka/gtk,grubersjoe/adwaita,grubersjoe/adwaita,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,Lyude/gtk-,davidgumberg/gtk,davidgumberg/gtk,ahodesuka/gtk,davidgumberg/gtk,alexlarsson/gtk,ahodesuka/gtk,jadahl/gtk,chergert/gtk,chergert/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,chergert/gtk,jadahl/gtk,Lyude/gtk-,Adamovskiy/gtk,jigpu/gtk,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,Lyude/gtk-,jigpu/gtk,Lyude/gtk-,alexlarsson/gtk,jigpu/gtk,alexlarsson/gtk,davidgumberg/gtk,Lyude/gtk-,chergert/gtk,alexlarsson/gtk,jadahl/gtk,jadahl/gtk,ahodesuka/gtk,alexlarsson/gtk,grubersjoe/adwaita,grubersjoe/adwaita,Adamovskiy/gtk,Adamovskiy/gtk,ahodesuka/gtk,alexlarsson/gtk