fix can't delete embedded file

See merge request !1781
24 jobs for for_testrunner_1 in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:27:25

passed ERP5.PerformanceTest-Master

00:27:04

failed ERP5.UnitTest-Master

02:27:47

failed ERP5.UnitTest-Zope2

04:20:26

passed SlapOS.Eggs.UnitTest-Master.Python2

00:25:59

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:24

passed Wendelin.UnitTest-Master

00:38:43

passed ERP5.CodingStyleTest-Master

00:51:27

passed ERP5.CodingStyleTest-Master

01:04:39

passed ERP5.PerformanceTest-Master

00:27:11

passed ERP5.PerformanceTest-Master

00:26:58

failed ERP5.UnitTest-Master

02:15:23

failed ERP5.UnitTest-Master

03:31:24

failed ERP5.UnitTest-Zope2

03:34:20

failed ERP5.UnitTest-Zope2

02:55:27

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:02

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:12

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:35

passed SlapOS.Eggs.UnitTest-Master.Python3

00:17:18

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:52

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:46

passed Wendelin.UnitTest-Master

00:40:36

passed Wendelin.UnitTest-Master

00:37:26

canceled Wendelin.UnitTest-Master

01:40:54