PTR deletions are performed against the collection

Author: cs278

lib/OpenCloud/DNS/Resource/PtrRecord.php

@@ -113,7 +113,8 @@ public function delete()
         }
 
         $url = clone $this->getUrl();
-        $url->addPath('rdns')
+        $url->addPath('..')
+            ->normalizePath()
             ->addPath($this->link_rel)
             ->setQuery($params);