Create Sidebar Widget in Visual Composer.php

/*
* At first retreive the sidebar list and return it in a array
*/
add_action('admin_init','treeservice_select_sidebar');
function  treeservice_select_sidebar() {
  $sidebar_list = array();
  foreach($GLOBALS['wp_registered_sidebars'] as $sidebar) {
    $sidebar_list[$sidebar['id']] = $sidebar['id'];
  }
  return $sidebar_list;
}

/*
*Shortcode for visual composer component
*/
function display_dynamic_sidebar_shortcode_callback($atts,$content=NULL) {
  extract(shortcode_atts( array('select_sidebar'=>'general-sidebar'), $atts));
  ob_start();
  if(is_active_sidebar( $select_sidebar )) {
    dynamic_sidebar($select_sidebar);
  }
  return ob_get_clean();
}
add_shortcode('display_dynamic_sidebar','display_dynamic_sidebar_shortcode_callback');

/*
*Visual Composer Component
*/
 add_action('vc_before_init', 'select_sidebar_component');
function select_sidebar_component() {
	$sidebar_list = treeservice_select_sidebar();
	vc_map(array(
		'name'     => __('Select Sidebar'),
		'base'     => 'display_dynamic_sidebar',
		'category' => __('BTS','tree-service'),
		'params'   => array(
			array(
			'type'        => 'dropdown',
			'heading'     => __('Select Sidebar'),
			'param_name'  => 'select_sidebar',
			'admin_label' => true,
			'value'       =>  $sidebar_list,
			'std'         => 'general-sidebar',
			)),
	));
}