Icon: Gdk.CairoContext does not exist

First of all 'Gdk.CairoContext' does not exist, this has been
made up by the conversion script in 820efa56b9

We do not need the previous gtk.gdk.CairoContext here anymore, we
do only want to set the background of the context here. See the
toolkit-gtk2 commit where this has been simplified [1].

[1] http://git.sugarlabs.org/sugar-toolkit/mainline/commit/6ce463585c3f3a639392e51cb26d789c2fde6516

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

src/sugar3/graphics/icon.py

@@ -278,7 +278,6 @@ class _IconBuffer(object):
             surface = cairo.ImageSurface(cairo.FORMAT_RGB24, int(width),
                                          int(height))
             context = cairo.Context(surface)
-            context = Gdk.CairoContext(context)
             context.set_source_color(self.background_color)
             context.paint()