ocarina: User cancels manual album art

This used to cause the album art to change to the Ocarina icon.  When
the user cancels setting album art, None is returned from the selector
function.  We should check for this before trying to set the image and
return early if path is None.

ocarina/components/image.py

@@ -97,6 +97,8 @@ class AlbumArt(gtk.EventBox):
 			return
 		from ocarina import fsselect
 		path = fsselect.file("Select an image")
+		if path == None:
+			return
 		print "Selected file: %s" % path
 		try:
 			#self.image.set(path)