fix ErrRpcStatus.GetCode() stack overflow (#352)

Co-authored-by: guyinyou <guyinyou.gyy@alibaba-inc.com>
diff --git a/golang/error.go b/golang/error.go
index 1105ea6..06fa590 100644
--- a/golang/error.go
+++ b/golang/error.go
@@ -30,7 +30,7 @@
 }
 
 func (err *ErrRpcStatus) GetCode() int32 {
-	return err.GetCode()
+	return err.Code
 }
 
 func (err *ErrRpcStatus) GetMessage() string {