move CloseTokenSource call out of defer (#3796)

Author: lantoli

main.go

@@ -10,8 +10,6 @@ import (
 )
 
 func main() {
-	defer config.CloseTokenSource() // Revoke SA token when the plugin is exiting because Terraform command finished.
-
 	var debugMode bool
 	flag.BoolVar(&debugMode, "debug", false, "set to true to run the provider with support for debuggers like delve")
 	flag.Parse()
@@ -25,7 +23,8 @@ func main() {
 		provider.MuxProviderFactory(),
 		serveOpts...,
 	)
+	config.CloseTokenSource() // Revoke SA token when the plugin is exiting because Terraform command finished.
 	if err != nil {
-		log.Println(err)
+		log.Fatal(err)
 	}
 }