Sync: fix purge for objects with uppercase chars

fixes #2627

doc/82-Changelog.md

@@ -16,6 +16,7 @@ v1.10.2 (unreleased)
 
 ### Import and Sync
 * FIX: triggering Sync manually produced an error on PostgreSQL (#2636)
+* FIX: purge stopped working for objects with uppercase characters (#2627)
 
 ### Configuration Baskets
 * FEATURE: more details shown in error messages related to invalid characters (#2646)

library/Director/Import/Sync.php

@@ -690,6 +690,7 @@ class Sync
         $noAction = [];
         $purgeAction = $this->rule->get('purge_action');
         foreach ($this->rule->purgeStrategy()->listObjectsToPurge() as $key) {
+            $key = strtolower($key);
             if (array_key_exists($key, $newObjects)) {
                 // Object has been touched, do not delete
                 continue;