if save fails clear login

CHANGELOG

@@ -17,6 +17,8 @@ minerva (16.0.0~beta.1) stable; urgency=medium
     create/update/delete (#1509)
   * Bug fix: exporting part of map as image caused removing not drawn species
     from the database (#1508)
+  * Bug fix: adding user with already existing login and changing his
+    privileges occured with error (#1507)
 
  -- Piotr Gawron <piotr.gawron@uni.lu>  Wed, 9 Jun 2021 15:00:00 +0200
 

frontend-js/src/main/js/gui/admin/EditUserDialog.js

@@ -598,6 +598,7 @@ EditUserDialog.prototype.onSaveClicked = function () {
     user.setName(self.getName());
     user.setSurname(self.getSurname());
     return self.getServerConnector().addUser(user).catch(function (error) {
+      user.setLogin(undefined);
       if (error instanceof ObjectExistsError) {
         return Promise.reject(new ValidationError("User with given login already exists"));
       }