Comment 2 for bug 1409545

I uploaded into gerrit the quick fix patch I wrote for our client, but I gave it a -2 to indicate the further issues we should also tackle. https://reviews.mahara.org/#/c/4137/

The code that causes this problem is quite old (probably from Mahara 1.6), so it probably affects 1.8 and 1.9 as well, but since it only throws a warning message and doesn't cause any other problems, it's probably not worth backporting further than 1.10.