Fixed compile error: Cannot declare class WarningField

platforms/joomla/plg_system_gantry5/gantry5.php

@@ -335,8 +335,6 @@ class plgSystemGantry5 extends CMSPlugin
         $task   = $input->getCmd('task');
 
         if (in_array($option, array('com_templates', 'com_advancedtemplates'), true)) {
-            // Register field class with namespace
-            require_once __DIR__ . '/fields/warning.php';
 
             if ($task && strpos($task, 'style') === 0 && $this->params->get('use_assignments', true)) {
                 // Get all ids.

platforms/joomla/plg_system_gantry5/gantry5.xml

@@ -13,7 +13,6 @@
     <files>
         <filename plugin="gantry5">gantry5.php</filename>
         <filename>MD5SUMS</filename>
-        <folder>fields</folder>
         <folder>forms</folder>
         <folder>language</folder>
     </files>