Bug 10921: Prevent an order from a closed basket to be edited

Bug 10921: Prevent an order from a closed basket to be edited

We don't allow editing of orders that are part of a closed basket, but
we don't enforce the rule in the controller file.

This patch use output_and_exit to stop the script and display an error
to the end user.

Test plan:
Create a basket, add an order
On the basket view you see the "Modify" link, open it in a separate tab
=> You can edit the basket
Keep this tab open, get back to the other one and close the basket
Reload the tab with the order edition form
=> You cannot longer edit the basket

QA: Do we need a check in addorder.pl as well?

Signed-off-by: Henry Bolshaw <bolshawh@parliament.uk>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>