httplib: fix unstable test, do not use httplib.org

adapter/grace/grace.go

@@ -18,28 +18,30 @@
 // Usage:
 //
 // import(
-//   "log"
-//	 "net/http"
-//	 "os"
 //
-//   "github.com/beego/beego/v2/server/web/grace"
+//	  "log"
+//		 "net/http"
+//		 "os"
+//
+//	  "github.com/beego/beego/v2/server/web/grace"
+//
 // )
 //
-//  func handler(w http.ResponseWriter, r *http.Request) {
-//	  w.Write([]byte("WORLD!"))
-//  }
+//	 func handler(w http.ResponseWriter, r *http.Request) {
+//		  w.Write([]byte("WORLD!"))
+//	 }
 //
-//  func main() {
-//      mux := http.NewServeMux()
-//      mux.HandleFunc("/hello", handler)
+//	 func main() {
+//	     mux := http.NewServeMux()
+//	     mux.HandleFunc("/hello", handler)
 //
-//	    err := grace.ListenAndServe("localhost:8080", mux)
-//      if err != nil {
-//		   log.Println(err)
-//	    }
-//      log.Println("Server on 8080 stopped")
-//	     os.Exit(0)
-//    }
+//		    err := grace.ListenAndServe("localhost:8080", mux)
+//	     if err != nil {
+//			   log.Println(err)
+//		    }
+//	     log.Println("Server on 8080 stopped")
+//		     os.Exit(0)
+//	   }
 package grace
 
 import (