How to remove admin bar logo in WordPress using plugin

This one does the job for us, we use WP3.7.1.

function no_wp_logo_admin_bar_remove() {
    global $wp_admin_bar;
    $wp_admin_bar->remove_menu('wp-logo');
}
add_action('wp_before_admin_bar_render', 'no_wp_logo_admin_bar_remove', 0);