Fix radiopalette due to api change in toolbotton

Signed-off-by: Gonzalo Odiard <gonzalo@laptop.org>
Acked-by: Simon Schampijer <simon@laptop.org>

src/sugar3/graphics/radiopalette.py

@@ -100,5 +100,5 @@ class RadioPalette(Palette):
             return
 
         parent.props.label = button.palette_label
-        parent.set_icon(button.props.icon_name)
+        parent.set_icon_name(button.props.icon_name)
         parent.selected_button = button