dont tag if tag_path is empty

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

ast.go

@@ -20,6 +20,9 @@ var (
 )
 
 func (g *Generator) astGenerate(plugin *protogen.Plugin) error {
+	if g.tagPath == "" {
+		return nil
+	}
 	for _, file := range plugin.Files {
 		if !file.Generate {
 			continue

main.go

@@ -13,7 +13,7 @@ var (
 	flagDebug      = flag.Bool("debug", false, "")
 	flagStandalone = flag.Bool("standalone", false, "")
 	flagComponents = flag.String("components", "micro|rpc|http|client|server", "")
-	flagTagPath    = flag.String("tag_path", ".", "")
+	flagTagPath    = flag.String("tag_path", "", "")
 )
 
 func main() {