Bug 12847: Items issued today is considered as overdue

Bug 12847: Items issued today is considered as overdue

The date comparisons in C4::Members::IssueSlip does not work as
expected.
Is an item is issue yesterday and due today (23:59), it should not be
considered as an overdue yet.

Test plan:
Define a valid issue slip (code ISSUESLIP)
Check 2 items out and update the issuedate value for one of them as
yesterday (using the mariadb/mysql cli or similar)
Print the slip
Before this patch the item marked as issued yesterday is considered as
overdue.

Special cases:
- hourly loans
- Quick slip is impacted too

Signed-off-by: Nick Clemens <nick@quecheelibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Bug 13601 is not in 3.18.x, so I removed the change connected
to that and it still tested ok.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>