a small inconsistency in summary cookie updation

[Manish <mailtomanish.sharma@gmail.com>]

I noticed a small inconsistency.  If you start with following sample
org file and press C-c C-c in the first cookie, it doesn't get updated
correctly whereas the second one does.  The only difference is that
one has children TODO tasks and the other has a list of checkboxes.

Starting file:

--8<---------------cut here---------------start------------->8---
* Item 1 [/]
  1. [X] line 1
  2. [ ] line 2
* Item 2 [/]
*** TODO Sub-item 2.1
*** DONE Sub-item 2.2
--8<---------------cut here---------------end--------------->8---

Status after C-c C-c in the summary cookie.

--8<---------------cut here---------------start------------->8---
* Item 1 [0/0]
  1. [X] line 1
  2. [ ] line 2
* Item 2 [1/2]
*** TODO Sub-item 2.1
*** DONE Sub-item 2.2
--8<---------------cut here---------------end--------------->8---

Thanks
-- 
Manish