Add TLS encryption capability to RPC clients (#2789)

cmd/control-shutdown-main.go

@@ -66,6 +66,7 @@ func shutdownControl(c *cli.Context) {
 	authCfg := &authConfig{
 		accessKey:   serverConfig.GetCredential().AccessKeyID,
 		secretKey:   serverConfig.GetCredential().SecretAccessKey,
+		secureConn:  parsedURL.Scheme == "https",
 		address:     parsedURL.Host,
 		path:        path.Join(reservedBucket, controlPath),
 		loginMethod: "Controller.LoginHandler",