修正示例代码.

Signed-off-by: chen.yang <chen.yang@yuzhen-iot.com>

Software/Development/Language/Go/Package/Go_语言_flag_包基本使用.md

@@ -99,17 +99,15 @@ import (
     "fmt"
 )
 
-func init(){
-    flag.Usage = usage
-    flag.Parse()
-}
-
 func usage(){
-  fmt.Print("nginx version v1.12")
+  fmt.Println("nginx version v1.12")
   flag.PrintDefaults()
 }
 
-func main(){}
+func main(){
+    flag.Usage = usage
+    flag.Parse()
+}
 ```
 
 ### 3.5.flag 其他函数