Display of un-assigned sections into the "workbench access" select list in the node form

The module workbench_access_view is revealing a small incompatibility with workbench_access: users of roles that have been assign as a viewers only to a particular editorial section WILL SEE this editorial section in the Editorial section select list in node form when creating or updating a node.

To reproduce:

1. Enable modules workbench_access and workbench_access_view
2. Create a editorial section taxonomy with:
   • Parent A
     • Child A1
     • Child A2
   • Parent B
3. Use this taxonomy as editorial section in workbench access module
4. Create a role "Editor A1"
5. Assign to role "Editor A1" editor permission on section "Child A1"
6. Assign to role "Editor A1" viewer permission on section "Parent A"
7. Log as a user having the role "Editor A1"
8. Visit a node creation page: in the editorial section select list: you will see all sections underneath "Parent A": "Child A1" and "Child A2": BUG : we should not see "Child A2"

This bug is minored by the fact that IF a node has already been assigned to section "Child A2", it won't be editable by a user "Editor A1" in this example.

I think that this is just the way the select list is build that is wrong.