Comment 21 for bug 1177830

Here is a patch for Essex which fixes the bug. It does not add a test case, but it has been manually tested with both use_cow_images=true and use_cow_images=false with flavors with unspecified root size, too small root size and big enough root size.

However, it introduces a regression in that if exception.ImageTooLarge() is raised, the flavor cannot be deleted:
$ nova flavor-list
...
| 8 |small1 | 256 | 1 | 1 | | 1 | 1.0 |
$ nova flavor-delete 8
ERROR: The resource could not be found. (HTTP 404)