update socket编程部分 readAll -> read

go version go1.11.5 darwin/amd64
执行socket client/server示例报错，read: connection reset by peer
原因是readAll要一直读到EOF才结束，server端已断开连接

Author: tilics

zh/08.1.md

@@ -149,7 +149,9 @@ func main() {
 	checkError(err)
 	_, err = conn.Write([]byte("HEAD / HTTP/1.0\r\n\r\n"))
 	checkError(err)
-	result, err := ioutil.ReadAll(conn)
+	// result, err := ioutil.ReadAll(conn)
+	result := make([]byte, 256)
+	_, err = conn.Read(result
 	checkError(err)
 	fmt.Println(string(result))
 	os.Exit(0)