Bug 14636: Item search - fix search and sort by publication date for MARC21

Problem: MARC21/NORMARC stores the publication
date in biblio.copyrightdate, but UNIMARC uses
biblioitems.publicationyear.

To test:
- Without patch in a MARC21 installation:
- Search by publication date
- Verify that the results don't match the
  publication year you searched for.
- Try sorting the table by publication year.
- Verify that the sort doesn't work.
- Apply patch.
- Repeat both, search and sort.
- Verify both work correctly now.
- Repeat tests on a UNIMARC installation.
- Verify both still work.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>

Tested searching and sorting successfully in a MARC21 installation. DID
NOT test in UNIMARC.

Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit 0d2e83bca5)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>

catalogue/itemsearch.pl

@@ -128,6 +128,9 @@ if (scalar keys %params > 0) {
         my $op = shift @op;
         if (defined $q and $q ne '') {
             if ($i == 0) {
+                if (C4::Context->preference("marcflavor") ne "UNIMARC" && $field eq 'publicationdate') {
+                    $field = 'copyrightdate';
+                }
                 $f = {
                     field => $field,
                     query => $q,
@@ -181,10 +184,15 @@ if (scalar keys %params > 0) {
         };
     }
 
+    my $sortby = $cgi->param('sortby') || 'itemnumber';
+    if (C4::Context->preference("marcflavor") ne "UNIMARC" && $sortby eq 'publicationyear') {
+        $sortby = 'copyrightdate';
+    }
+    warn $sortby;
     my $search_params = {
         rows => $cgi->param('rows') // 20,
         page => $cgi->param('page') || 1,
-        sortby => $cgi->param('sortby') || 'itemnumber',
+        sortby => $sortby,
         sortorder => $cgi->param('sortorder') || 'asc',
     };