Bug 14016: Restore correct date format on issue date (00:00 vs 23:59)

Introduced by bug 13601, and same fix used in bug 10423 and bug 12847:
the date_due retrieved from the DB is modified.

There are some problems:
1/ There is confusion between the iso and sql formats in the codebase.
2/ Since bug 13601, dt_from_string does not manage the iso format (there
are occurrences of 'iso' but it assumes that both formats are
identical).

To solve the issue, 2 solutions:
1/ Same as bug 10423 and bug 12847: try to get rid of the change done on
date_due in C4::Members::GetPendingIssues, it should be kept as the sql
value.
2/ Too many errors found and another fallback should be added to
dt_from_string (if 'iso' is passed, try sql then iso).

Test plan:
Go on the checkout list at the OPAC and confirm that the due dates are
correctly formatted.

Signed-off-by: Nicolas Legrand <nicolas.legrand@bulac.fr>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>

C4/Members.pm

@@ -1199,6 +1199,8 @@ sub GetPendingIssues {
         if ($_->{issuedate}) {
             $_->{issuedate} = dt_from_string($_->{issuedate}, 'sql');
         }
+        $_->{date_due_sql} = $_->{date_due};
+        # FIXME no need to have this value
         $_->{date_due} or next;
         $_->{date_due_sql} = $_->{date_due};
         # FIXME no need to have this value

koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-user.tt

@@ -191,14 +191,14 @@
                                                     <td class="date_due overdue">
                                                         <span title="[% ISSUE.date_due %]">
                                                             <span class="tdlabel">Date due:</span>
-                                                            [% ISSUE.date_due | $KohaDates as_due_date => 1 %]
+                                                            [% ISSUE.date_due_sql | $KohaDates as_due_date => 1 %]
                                                         </span>
                                                     </td>
                                                 [% ELSE %]
                                                     <td class="date_due">
                                                         <span title="[% ISSUE.date_due %]">
                                                             <span class="tdlabel">Date due:</span>
-                                                            [% ISSUE.date_due | $KohaDates as_due_date => 1 %]
+                                                            [% ISSUE.date_due_sql | $KohaDates as_due_date => 1 %]
                                                         </span>
                                                     </td>
                                                 [% END %]