make rhash optional

telegram/telegram.go

@@ -83,6 +83,9 @@ func NewTelegramSender(transport http.RoundTripper, authToken string) TelegramSe
 }
 
 func genIVLink(link, rhash string) string {
+	if rhash == "" {
+		return link
+	}
 	query := url.Values{}
 	query.Set("url", link)
 	query.Set("rhash", rhash)