[1.1.X] Moved _get_foreign_key call after testing for fk_name fixing a broken test.

def validate_inline(cls, parent, parent_model):

    fk = _get_foreign_key(parent_model, cls.model, fk_name=cls.fk_name, can_fail=True)

    # model is already verified to exist and be a Model

    if cls.fk_name: # default value is None

        f = get_field(cls, cls.model, cls.model._meta, 'fk_name', cls.fk_name)

        if not isinstance(f, models.ForeignKey):

            raise ImproperlyConfigured("'%s.fk_name is not an instance of "

                    "models.ForeignKey." % cls.__name__)

    fk = _get_foreign_key(parent_model, cls.model, fk_name=cls.fk_name, can_fail=True)

    # extra = 3

    # max_num = 0

    for attr in ('extra', 'max_num'):