ERP5Type/RelatedAccessor: fix catalog warning for discarded empty values

5 jobs for fix/crm_report_0_test in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

10:16:54

failed ERP5.UnitTest-Master

failed ERP5.UnitTest-Master.Medusa

14:38:01

passed SlapOS.Eggs.UnitTest-Master.Python2

00:35:59

passed SlapOS.Eggs.UnitTest-Master.Python2

00:19:54