Alert: fix for traceback in the draw - SL #4251

The Gtk.StyleContext get_background_color method needs a
Gtk.StateFlags as a parameter.  Feeding it with a GtkStateType doesn't
work anymore in recent gtk+.

Signed-off-by: Manuel Quiñones <manuq@laptop.org>
Acked-by: Simon Schampijer <simon@laptop.org>

src/sugar3/graphics/alert.py

@@ -370,7 +370,7 @@ class _TimeoutIcon(Gtk.Alignment):
         radius = w / 2
         context.arc(x, y, radius, 0, 2 * math.pi)
         widget_style = self.get_style_context()
-        color = widget_style.get_background_color(self.get_state())
+        color = widget_style.get_background_color(self.get_state_flags())
         context.set_source_rgb(color.red, color.green, color.blue)
         context.fill_preserve()