gtk-window-decorator: decorator.c : a small typo error

in gtk-window-decorator: decorator.c : update_window_decoration_icon (WnckWindow *win)

we should use 'style_window_rgb' instead of 'style_window_rgba'when in reparenting mode:
////////////////////////////
/* 32 bit pixmap on pixmap mode, 24 for reparenting */
 if (d->frame_window)
     d->icon_pixmap = pixmap_new_from_pixbuf (d->icon_pixbuf,
           d->frame->style_window_rgba);
 else
     d->icon_pixmap = pixmap_new_from_pixbuf (d->icon_pixbuf,
           d->frame->style_window_rgb);
//////////////////////////////

there isn't any bugs related to this. but i think it should be corrected.