[1.6.x] Removed unused model option "admin"

Backport of 5df84b268d from master

django/db/models/options.py

@@ -41,7 +41,6 @@ class Options(object):
         self.get_latest_by = None
         self.order_with_respect_to = None
         self.db_tablespace = settings.DEFAULT_TABLESPACE
-        self.admin = None
         self.meta = meta
         self.pk = None
         self.has_auto_field, self.auto_field = False, None

docs/ref/models/options.txt

@@ -222,9 +222,8 @@ Django quotes column and table names behind the scenes.
 .. attribute:: Options.permissions
 
     Extra permissions to enter into the permissions table when creating this object.
-    Add, delete and change permissions are automatically created for each object
-    that has ``admin`` set. This example specifies an extra permission,
-    ``can_deliver_pizzas``::
+    Add, delete and change permissions are automatically created for each
+    model. This example specifies an extra permission, ``can_deliver_pizzas``::
 
         permissions = (("can_deliver_pizzas", "Can deliver pizzas"),)