[1.0.X] Fixed #9608: Ensured a Model's default repr() is printable even if its...

[1.0.X] Fixed #9608: Ensured a Model's default repr() is printable even if its unicode method raises a Unicode error.

r9475 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9477 bcc190cf-cafb-0310-a4f2-bffc1f526a37