Revert "Add related config fallback" (#753)

module/VuFind/src/VuFind/RecordDriver/AbstractBase.php

@@ -375,12 +375,8 @@ abstract class AbstractBase implements \VuFind\Db\Table\DbTableAwareInterface,
     public function getRelated(\VuFind\Related\PluginManager $factory, $types = null)
     {
         if (is_null($types)) {
-            if (isset($this->recordConfig->Record->related)) {
-                $types = $this->recordConfig->Record->related;
-            } else {
-                $types = isset($this->mainConfig->Record->related) ?
-                    $this->mainConfig->Record->related : [];
-            }
+            $types = isset($this->recordConfig->Record->related) ?
+                $this->recordConfig->Record->related : [];
         }
         $retVal = [];
         foreach ($types as $current) {