[1.0.X] Fixed #10149. FileFields? in a form now validate max_length. Based on...

[1.0.X] Fixed #10149. FileFields? in a form now validate max_length. Based on a patch by Massimo Scamarcia. Backport of r10227 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10232 bcc190cf-cafb-0310-a4f2-bffc1f526a37