Bug 27945: Clarify 'same day' behavior

Bug 27945: Clarify 'same day' behavior

This patch introduces tests for the 'same day' check of the ability to
place article requests for a patron.

The limit goes against current requests, and those that have been
completed on the same day. The tests cover this specific situation.

The current behavior is that it takes into account a 24 hr timespan, but
consensus on the QA step was that we should do it as 'same day' and use
a separate feature request to change this, if required.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/Koha/Patron.t
=> SUCCESS: Tests pass!
3. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>