Bug 534266 - Quick patch waiting for review

["A. Walton" <awalton gnome org>]

http://bugzilla.gnome.org/show_bug.cgi?id=534226
Bug 534226 – Crash in nautilus-icon-dnd.c on bad pixmap

The transparency-on-dragged-icon change in rev 13739
(http://svn.gnome.org/viewvc/nautilus?view=revision&revision=13739)
introduced a tiny issue when nautilus_icon_canvas_item_get_image()
returns NULL (it apparently can/does happen, as the crash is
reproducible).

Thanks,
-A.Walton