Made legacy `ObjectPaginator` truly backwards-compatible by catching both...

Made legacy `ObjectPaginator` truly backwards-compatible by catching both `AttributeError` and `TypeError` in `_get_count` as it did before 
[7306].  Tests included.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7819 bcc190cf-cafb-0310-a4f2-bffc1f526a37