/**
 * Implements hook_field_storage_delete().
 */
function {{ machine_name }}_field_storage_delete($entity_type, $entity, $fields) {
  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

  foreach (field_info_instances($entity_type, $bundle) as $instance) {
    if (isset($fields[$instance['field_id']])) {
      $field = field_info_field_by_id($instance['field_id']);
      field_sql_storage_field_storage_purge($entity_type, $entity, $field, $instance);
    }
  }
}