Bug 37587: Fix priority of multiple item-level holds

The rank parameter is passed per biblio record, not per item. When
placing multiple item-level holds on one bib record, only $rank[0] is
defined.

To test:
1. System preference and circulation rule setup
    i. Set the system preference DisplayMultiItemHolds to Enable
    ii. Edit the default circulation rule to allow 5 holds per record
2. Find or create a bib with 4 or more items
3. Place several bib-level holds
4. Place 4 or more item-level holds at once on that same record
    i. Search for a patron to place the holds for (not one of the
       patrons you used in step 3)
    ii. Select "Hold a specific item"
    iii. Check the checkboxes for 4 or more items
    iv. Click Place hold
--> Note that one of the new item-level holds is at the end of the list
    as it should be, but the rest are out of order
5. Cancel the item-level holds from step 4
6. Apply patch and restart_all
7. Repeat step 4
--> All the new item-level holds are now at the end of the list

Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Paul Derscheid <paul.derscheid@lmscloud.de>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>

Author: Emily Lamancusa

reserve/placerequest.pl

@@ -73,6 +73,9 @@
 
         my $can_override = C4::Context->preference('AllowHoldPolicyOverride');
         if ( @checkitems ) {
+
+            my $hold_priority = $rank[0];
+
             for ( my $i = 0 ; $i < scalar @checkitems ; $i++ ) {
                 my $checkitem = $checkitems[$i];
                 if ( my $item_pickup_location = $input->param("item_pickup_$checkitem") ) {
@@ -93,7 +96,7 @@
                                 branchcode       => $item_pickup_location,
                                 borrowernumber   => $patron->borrowernumber,
                                 biblionumber     => $biblionumber,
-                                priority         => $rank[$i],
+                                priority         => $hold_priority,
                                 reservation_date => $startdate,
                                 expiration_date  => $expirationdate,
                                 notes            => $notes,
@@ -105,6 +108,8 @@
                             }
                         );
 
+                        $hold_priority++;
+
                     } else {
                         $failed_holds{$can_item_be_reserved} = 1;
                     }