icontheme: Make sure icon_info->scale doesn't end up 0
icontheme: Make sure icon_info->scale doesn't end up 0

GdkPixbuf will fail returning %NULL if we try to scale a pixbuf to (0, 0),
which will then trigger an assertion in gtk_icon_info_load_icon_finish();
we never want a scale of 0, so ensure it is at least 1.

https://bugzilla.gnome.org/show_bug.cgi?id=708384

jessevdk/gtk,alexlarsson/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,davidgumberg/gtk,ahodesuka/gtk,chergert/gtk,msteinert/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,davidgumberg/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk,chergert/gtk,Adamovskiy/gtk,jessevdk/gtk,Lyude/gtk-,Lyude/gtk-,jessevdk/gtk,msteinert/gtk,davidgumberg/gtk,alexlarsson/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,ahodesuka/gtk,chergert/gtk,jadahl/gtk,grubersjoe/adwaita,Adamovskiy/gtk,msteinert/gtk,Adamovskiy/gtk,jigpu/gtk,msteinert/gtk,alexlarsson/gtk,jigpu/gtk,msteinert/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,Lyude/gtk-,Lyude/gtk-,jadahl/gtk,Adamovskiy/gtk,Adamovskiy/gtk,chergert/gtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,jigpu/gtk,grubersjoe/adwaita,jessevdk/gtk,alexlarsson/gtk,Adamovskiy/gtk,Lyude/gtk-,davidgumberg/gtk,ahodesuka/gtk,chergert/gtk,ahodesuka/gtk,ahodesuka/gtk,davidgumberg/gtk,jadahl/gtk,grubersjoe/adwaita,jigpu/gtk,jadahl/gtk,jessevdk/gtk,Lyude/gtk-,ahodesuka/gtk,msteinert/gtk,jigpu/gtk,grubersjoe/adwaita,jadahl/gtk,jadahl/gtk,jessevdk/gtk,jessevdk/gtk,davidgumberg/gtk,chergert/gtk,ahodesuka/gtk,Lyude/gtk-,jigpu/gtk,Sidnioulz/SandboxGtk,davidgumberg/gtk,grubersjoe/adwaita,alexlarsson/gtk,chergert/gtk,jigpu/gtk,Sidnioulz/SandboxGtk,chergert/gtk,ahodesuka/gtk