ocarina: Catch exception on empty album art file

I don't want to set the image to an empty file.  Improving the cache so
that it doesn't store empty files is the best solution, so for now I
just check the error (and keep the function from uninviting itself from
the POSTGETART event)

ocarina/body/image.py

@@ -14,7 +14,10 @@ def find_new_width(buf, new_h):
 	return (float(w) / float(h)) * new_h
 
 def resize(img, new_h):
-	buf = img.get_pixbuf()
+	try:
+		buf = img.get_pixbuf()
+	except Exception, e:
+		return
 	if buf == None:
 		return
 	new_w = find_new_width(buf, new_h)