Not support host contains port,such as http://example:8000/something

[hhofchina]

fix http.go:47

//       ips, err := net.LookupIP(parsed.Host) 
        host := parsed.Host
        if strings.LastIndex(host, ":") != -1 {
		host = parsed.Host[:strings.LastIndex(host, ":")]
	}
	ips, err := net.LookupIP(host)