[nautilus] desktop-icon-view: don't unconditionally unref the desktop background

[Cosimo Cecchi <cosimoc src gnome org>]

commit ebee13eef39824ebe536d0e42a35337097a33942
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Sat Oct 30 14:35:47 2010 +0200

    desktop-icon-view: don't unconditionally unref the desktop background

 src/file-manager/fm-desktop-icon-view.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/file-manager/fm-desktop-icon-view.c b/src/file-manager/fm-desktop-icon-view.c
index e04b14a..19cabfd 100644
--- a/src/file-manager/fm-desktop-icon-view.c
+++ b/src/file-manager/fm-desktop-icon-view.c
@@ -300,7 +300,10 @@ fm_desktop_icon_view_dispose (GObject *object)
 					      fm_directory_view_update_menus,
 					      icon_view);
 
-	g_object_unref (icon_view->details->background);
+	if (icon_view->details->background != NULL) {
+		g_object_unref (icon_view->details->background);
+		icon_view->details->background = NULL;
+	}
 
 	G_OBJECT_CLASS (fm_desktop_icon_view_parent_class)->dispose (object);
 }