fix golangci-lint failed (#284)

* fix golangci-lint error

officialaccount/message/customer_message.go

@@ -147,6 +147,9 @@ func (manager *Manager) Send(msg *CustomerMessage) error {
 	}
 	uri := fmt.Sprintf("%s?access_token=%s", customerSendMessage, accessToken)
 	response, err := util.PostJSON(uri, msg)
+	if err != nil {
+		return err
+	}
 	var result util.CommonError
 	err = json.Unmarshal(response, &result)
 	if err != nil {

officialaccount/message/template.go

@@ -59,7 +59,9 @@ func (tpl *Template) Send(msg *TemplateMessage) (msgID int64, err error) {
 	}
 	uri := fmt.Sprintf("%s?access_token=%s", templateSendURL, accessToken)
 	response, err := util.PostJSON(uri, msg)
-
+	if err != nil {
+		return
+	}
 	var result resTemplateSend
 	err = json.Unmarshal(response, &result)
 	if err != nil {

officialaccount/message/transfer_customer.go

@@ -13,11 +13,11 @@ type TransInfo struct {
 }
 
 //NewTransferCustomer 实例化
-func NewTransferCustomer(KfAccount string) *TransferCustomer {
+func NewTransferCustomer(kfAccount string) *TransferCustomer {
 	tc := new(TransferCustomer)
-	if KfAccount != "" {
+	if kfAccount != "" {
 		transInfo := new(TransInfo)
-		transInfo.KfAccount = KfAccount
+		transInfo.KfAccount = kfAccount
 		tc.TransInfo = transInfo
 	}
 	return tc