增加性接口，修复登录错误

pkg/httpclient/resty.go

@@ -23,7 +23,7 @@ func SDULogin(username string, password string) (*dto.SDULoginData, error) {
 	}
 	result1 := string(resp.Body())
 	if resp.StatusCode()/100 != 2 {
-		return nil, errors.New(result1)
+		return nil, errors.New("账号或密码错误")
 	}
 	resp, err = Client.R().SetBody("service=https://service.sdu.edu.cn/tp_up/view?m=up").
 		Post("https://pass.sdu.edu.cn/cas/restlet/tickets/" + result1)