Fixed #28834 -- Followed ancestor links on field cache lookup failure.

Thanks Tim for the review.

tests/model_inheritance/models.py

@@ -178,6 +178,7 @@ class GrandParent(models.Model):
     first_name = models.CharField(max_length=80)
     last_name = models.CharField(max_length=80)
     email = models.EmailField(unique=True)
+    place = models.ForeignKey(Place, models.CASCADE, null=True, related_name='+')
 
     class Meta:
         unique_together = ('first_name', 'last_name')