Update objectclasses for groups, by default not posix groups.

This change depends on DS bugs 487574 and 487725. Groups cannot be
promoted properly without these fixed. It will fail with an
Object Class violation because gidNumber isn't set.

ipaserver/plugins/b_ldap.py

@@ -202,7 +202,7 @@ class ldap(CrudBackend):
         if attribute == "uid": # User
             object_type = "posixAccount"
         elif attribute == "cn": # Group
-            object_type = "posixGroup"
+            object_type = "ipaUserGroup"
         elif attribute == "krbprincipalname": # Service
             object_type = "krbPrincipal"