refs #20764 [vufing] undo comments in vufind to sync with dev

* use EzbTrait.php for PR
This reverts commit 6f1cc98c.

module/VuFind/src/VuFind/Resolver/Driver/Ezb.php

@@ -6,7 +6,7 @@
  * http://services.dnb.de/fize-service/gvr/full.xml
  *
  * API documentation is available at
- * http://www.zeitschriftendatenbank.de/services/journals-online-print
+ * http://www.zeitschriftendatenbank.de/services/schnittstellen/journals-online-print
  *
  * PHP version 7
  *
@@ -136,7 +136,7 @@ class Ezb extends AbstractBase
     public function getResolverUrl($openURL)
     {
         // Unfortunately the EZB-API only allows OpenURL V0.1 and
-        // breaks when sending a non expected parameter.
+        // breaks when sending a non expected parameter (like an ISBN).
         // So we do have to 'downgrade' the OpenURL-String from V1.0 to V0.1
         // and exclude all parameters that are not compliant with the EZB.
 
@@ -216,9 +216,9 @@ class Ezb extends AbstractBase
                 }
                 if ($newKey !== false) {
                     $downgraded[] = "$newKey=$value";
+                }
             }
         }
-        }
 
         return implode('&', $downgraded);
     }