Comment 2 for bug 1208417

I check the mysql, here are some problematic entries:

mysql> select * from image_properties where name='kernel_id';
+-----+--------------------------------------+-----------+-------+---------------------+---------------------+------------+---------+
| id | image_id | name | value | created_at | updated_at | deleted_at | deleted |
+-----+--------------------------------------+-----------+-------+---------------------+---------------------+------------+---------+
| 7 | ac9990ad-b3ac-45ea-8c2e-ddf45dd10791 | kernel_id | None | 2013-08-05 08:02:52 | 2013-08-05 08:02:52 | NULL | 0 |
| 20 | bcb7fe30-0561-42ae-8adf-d0decc1dbe07 | kernel_id | None | 2013-08-05 08:11:04 | 2013-08-05 08:11:04 | NULL | 0 |

The value of kernel_id shoud be NULL instead of string 'None'.