Bug 15171: Display subscriptions which will expire in the future

Bug 15171: Display subscriptions which will expire in the future

Since the form on the subscription check expiration page let the user choose an
expiration date > today, there is no sense to hide subscriptions which will expire in the future.

Test plan:
0/ Make sure you have at least subscription with an expiration date > today
1/ Start a seach on the check expiration page (serials/checkexpiration.pl)
with a date < today, = today and > today
=> The subscription won't never be displayed without this patch.
With this patch, it will.

Note that you will get a "No results for your query" message only if you
have search for something.

Followed testplan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>