Fix OpenStruct use in ldap_spec

.rubocop_manual_todo.yml

@@ -2566,7 +2566,6 @@ Style/OpenStructUse:
     - 'ee/spec/helpers/ee/blob_helper_spec.rb'
     - 'ee/spec/lib/gitlab/auth/group_saml/failure_handler_spec.rb'
     - 'ee/spec/lib/gitlab/legacy_github_import/project_creator_spec.rb'
-    - 'ee/spec/requests/api/ldap_spec.rb'
     - 'lib/api/wikis.rb'
     - 'lib/gitlab/git/diff_collection.rb'
     - 'lib/gitlab/import_export/after_export_strategies/base_after_export_strategy.rb'

ee/spec/requests/api/ldap_spec.rb

@@ -13,8 +13,8 @@ RSpec.describe API::Ldap do
 
   before do
     groups = [
-      OpenStruct.new(cn: 'developers'),
-      OpenStruct.new(cn: 'students')
+      double('group', cn: 'developers'),
+      double('group', cn: 'students')
     ]
 
     allow(Gitlab::Auth::Ldap::Config).to receive(:enabled?).and_return(true)