Bug 17865 'If a subscription has no history end date, it shows as expired today in...

Bug 17865 'If a subscription has no history end date, it shows as expired today in OPAC'

--TEST PLAN--
1) View a subscription with no history end date
2) Search for an item with a subcription in OPAC
3) Under subscription tab click more details
4) The end date will be the current date
5) Apply patch and refresh
6) The end date will not be shown

Signed-off-by: Baptiste Wojtkowski <baptiste.wojtkowski@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>