'No slots available' not translatable

in function commerce_registration_get_product_title the line

    $availtext = ($avail > 0 ? format_plural($avail, '1 slot available', '@count slots available') : 'No slots available');

needs to be

    $availtext = ($avail > 0 ? format_plural($avail, '1 slot available', '@count slots available') : t('No slots available'));