Fixed #10118 -- Clarified the error message raised when accessing a subclass model that doesn't exist. Thanks to peterbraden@peterbraden.co.uk for the suggestion.
Fixed #10118 -- Clarified the error message raised when accessing a subclass model that doesn't exist. Thanks to peterbraden@peterbraden.co.uk for the suggestion.

git-svn-id: 554f83ef17aa7291f84efa897c1acfc5d0035373@9859 bcc190cf-cafb-0310-a4f2-bffc1f526a37

svn2github/django,svn2github/django,svn2github/django