Custom Entity support broken for 1 bundle 1 entity

I propose we change the way metatag_entity_supports_metatags handles entities with only one bundle to match the behavior in the UI.

IN metatag_entity_supports_metatags before we check the option for each bundle:

            // If only one bundle exists, take configuration for entity, to
            // reflect options as they are available in the UI.
            if (count($entity_info['bundles']) === 1) {
              $entity_types[$entity_name][$bundle_name] = !empty(variable_get('metatag_enable_' . $entity_name, FALSE));
              continue;
            }

See attached patch.

Note this fix works for our custom entities, and even though the configuration variable relating to its bundle:
metatag_enable_{$entity_name}_{$entity_name}
remains set to FALSE, this doesn't present a problem because if we add another bundle later on, the option to unset this will be available through the user interface.

Have fixed up the patch to remove the return value passed through as arg. Also removed accidental file mode change.