Bug 29240: (follow-up) Correct more instances

Bug 29240: (follow-up) Correct more instances

This patch fixes linked date fields in these pages:

 - Reports -> Patrons with the most checkouts
 - Reports -> Patrons statistics wizard
 - Reports -> Most-circulated items
 - Reports -> Catalog statistics wizard
 - Reports -> Guided reports
 - Reports -> Average loan time
 - Reports -> Holds statistics wizard

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>