[1.0.X] Fixed #10243, #11043 -- Corrected handling of formsets over a ForeignKey that uses to_field, and by extension, fixed the admin for handling fields of that type. Thanks to apollo13 for the initial patch.

Merge of r10756 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10758 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/model_formsets_regress/models.py

@@ -0,0 +1,9 @@
+from django.db import models
+
+class User(models.Model):
+    username = models.CharField(max_length=12, unique=True)
+    serial = models.IntegerField()
+
+class UserSite(models.Model):
+    user = models.ForeignKey(User, to_field="username")
+    data = models.IntegerField()