TwentyTwelve child theme style.css?ver=3.8.1

well that depends on what you want to do, but if it is easier for you to edit that template it will be better that you can control all the output of it.. fx like this

function add_require_scripts_files() {
 wp_enqueue_style('layout', get_template_directory_uri().'/style.css', array(), '1.0.0', "all");        
}


add_action( 'wp_enqueue_scripts', 'add_require_scripts_files' );

and this what the function expects as paramenters:

wp_enqueue_style( $handle, $src, $deps, $ver, $media );

and remember to remove the function that adds the css file in the init function.