function remove_revslider_meta_tag() { return ""; }

add_filter( 'revslider_meta_generator', 'remove_revslider_meta_tag' );

add_action('wp_head', 'myoverride', 1);
function myoverride() {
  if ( class_exists( 'Vc_Manager' ) ) {
    remove_action('wp_head', array(visual_composer(), 'addMetaData'));
  }
}

//remove a metatag (Powered by Visual Composer) from the wordpress
add_action('init', 'optimize_fixwp_head', 100);
function optimize_fixwp_head() {
   remove_action('wp_head', array(visual_composer(), 'addMetaData')); 
}