Bug 13946: Change order status 'Pending' to 'Ordered'

Bug 13946: Change order status 'Pending' to 'Ordered'

The order status after closing the basket is 'ordered' in the
database, but displays as 'pending' in the staff interface.

As we use 'pending' when you have to review a suggestion, this
clashes in translations and the meaning is different. The patch
renames 'pending' for the order status to 'Ordered' to be more
clear.

To test:
- Verfiy 'Ordered' shows in the pull down on the acq advanced
  search and search still works correctly
- Verify the results table also display 'Ordered' as the status

Signed-off-by: Cédric Vita <cedric.vita@dracenie.com>
Signed-off-by: Jonathan Druart <jonathan.druart@koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>