[ci skip]

* Now it's only created when user choose to create a MR and
  logic to hide it is handled by https://gitlab.com/gitlab-org/gitlab-ce/blob/50595af7b0e304f16e2955109abd2d25cd96efda/app/helpers/application_helper.rb#L139

* Now checking if a commit is already reverted or there is a conflict is
  much more faster.
* No longer need to create a new branch.