Doc: fix build script for ubuntu 16.04
Doc: fix build script for ubuntu 16.04

antoine-de/navitia,pbougue/navitia,CanalTP/navitia,kadhikari/navitia,antoine-de/navitia,xlqian/navitia,CanalTP/navitia,kinnou02/navitia,xlqian/navitia,patochectp/navitia,antoine-de/navitia,CanalTP/navitia,pbougue/navitia,Tisseo/navitia,Tisseo/navitia,pbougue/navitia,CanalTP/navitia,kinnou02/navitia,kadhikari/navitia,CanalTP/navitia,kadhikari/navitia,Tisseo/navitia,patochectp/navitia,antoine-de/navitia,patochectp/navitia,xlqian/navitia,Tisseo/navitia,kinnou02/navitia,pbougue/navitia,xlqian/navitia,Tisseo/navitia,kinnou02/navitia,xlqian/navitia,patochectp/navitia,kadhikari/navitia