[vala] libpanelapplet-2.0: Fix PanelApplet::change_background binding

[Jürg Billeter <juergbi src gnome org>]

commit 67e0745488d17849bbcbb39f43f74652d94c00d0
Author: Jürg Billeter <j bitron ch>
Date:   Fri Jul 10 15:13:29 2009 +0100

    libpanelapplet-2.0: Fix PanelApplet::change_background binding
    
    Based on patch by Yu Feng, fixes bug 555566.

 vapi/libpanelapplet-2.0.vapi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/vapi/libpanelapplet-2.0.vapi b/vapi/libpanelapplet-2.0.vapi
index 20e5b14..e80b6f9 100644
--- a/vapi/libpanelapplet-2.0.vapi
+++ b/vapi/libpanelapplet-2.0.vapi
@@ -30,7 +30,7 @@ namespace Panel {
 		public static int factory_main (string iid, GLib.Type applet_type, AppletFactoryCallback callback);
 		public void set_background_widget (Gtk.Widget widget);
 		public void setup_menu (string xml, [CCode (array_length = false)] BonoboUI.Verb[] verb_list, void* data);
-		public signal void change_background (AppletBackgroundType type, ref Gdk.Color color, Gdk.Pixmap pixmap);
+		public signal void change_background (AppletBackgroundType type, Gdk.Color? color, Gdk.Pixmap? pixmap);
 	}
 
 	[CCode (cprefix = "PANEL_")]