Create packages client/internal/ retry and lhttp.

client/internal/common/utils.go

Index: client/internal/common/utils.go
diff --git a/client/internal/common/utils.go b/client/internal/common/utils.go
index 08444498970c93d2885800bc39850c8a4fd04d0d..8aeaea646415770c7fb17c7357916d9325a7dbed 100644
--- a/client/internal/common/utils.go
+++ b/client/internal/common/utils.go
@@ -5,13 +5,10 @@
 package common
 
 import (
-	"errors"
 	"fmt"
 	"io"
-	"net/url"
 	"os"
 	"runtime"
-	"strings"
 	"time"
 
 	"github.com/luci/luci-go/client/internal/imported"
@@ -44,24 +41,6 @@ func SizeToString(s int64) string {
 	return fmt.Sprintf("%.2f%s", v, units[i])
 }
 
-// URLToHTTPS ensures the url is https://.
-func URLToHTTPS(s string) (string, error) {
-	u, err := url.Parse(s)
-	if err != nil {
-		return "", err
-	}
-	if u.Scheme != "" && u.Scheme != "https" {
-		return "", errors.New("Only https:// scheme is accepted. It can be omitted.")
-	}
-	if !strings.HasPrefix(s, "https://") {
-		s = "https://" + s
-	}
-	if _, err = url.Parse(s); err != nil {
-		return "", err
-	}
-	return s, nil
-}
-
 // IsDirectory returns true if path is a directory and is accessible.
 func IsDirectory(path string) bool {
 	fileInfo, err := os.Stat(path)