Bug 13196 - "Always show checkouts immediately" cookie should persist across sessions

Bug 13196 - "Always show checkouts immediately" cookie should persist across sessions

This patch modifies the way the checkouts script sets the "Always show
checkouts" cookie so that it is set with an explicit expiration date
(+365 days). This will allow the cookie to persist across browser
sesssions.

To test, apply the patch and clear your browser cookies to start with a
clean slate.

- Check out to a patron who has existing checkouts. Their checkouts
  should not load by default.
- Check the "Always show checkouts immediately" checkbox.
- Close your browser.
- Reopen your browser and check out to that patron again. Checkouts
  should now be displayed by default.

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
Works as described. I confirm that without this patch, the un-persistance of
"show checkouts" choice is very perturbing for librarians coming from previous
version of Koha.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes tests and QA script, no problems found.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>