[1.2.X] Fixed #14473 -- converted the model_package tests from doctests to...

[1.2.X] Fixed #14473 -- converted the model_package tests from doctests to unitests.  We have always been at war with doctests.  Thanks to Gabriel Hurley for the patch.  Backport of [14227].

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14228 bcc190cf-cafb-0310-a4f2-bffc1f526a37