Remove DbBackendForm::getConfig as it's not used anywhere

refs #5525

application/forms/Config/Authentication/DbBackendForm.php

@@ -81,23 +81,6 @@ class DbBackendForm extends BaseBackendForm
         );
     }
 
-    /**
-     * Return the datatbase authentication backend configuration for this form
-     *
-     * @return  array
-     *
-     * @see     BaseBackendForm::getConfig()
-     */
-    public function getConfig()
-    {
-        return array(
-            $this->getValue('name') => array(
-                'backend'   => 'db',
-                'resource'  => $this->getValue('resource')
-            )
-        );
-    }
-
     /**
      * Validate the current configuration by creating a backend and requesting the user count
      *