Merge branch 'dz-fix-autocomplete-spec' into 'master'

Fix failure in spec/services/groups/autocomplete_service_spec.rb

Closes #8777

See merge request gitlab-org/gitlab-ee!8766

ee/spec/services/groups/autocomplete_service_spec.rb

@@ -88,7 +88,7 @@ describe Groups::AutocompleteService do
     let!(:subgroup_milestone) { create(:milestone, group: sub_group) }
 
     before do
-      sub_group.add_guest(user)
+      sub_group.add_master(user)
     end
 
     context 'when group is public' do