tests: repair --random_activity_priority argument

This stopped working when the signature of Message.__init__ changed in
06aee0c2 (CMFActivity.ActivityTool: Use uid for identity check instead of
oid., 2019-09-17)
22 jobs for fix/edit_action in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:27:07

failed ERP5.PerformanceTest-Master

00:25:43

failed ERP5.UnitTest-Master

01:37:20

failed ERP5.UnitTest-Master.Medusa

02:16:49

passed SlapOS.Eggs.UnitTest-Master.Python2

00:09:59

passed SlapOS.Eggs.UnitTest-Master.Python3

00:11:10

failed ERP5.UnitTest-Master

01:13:07

failed ERP5.UnitTest-Master

04:06:55

failed ERP5.UnitTest-Master

02:08:12

failed ERP5.UnitTest-Master

01:23:43

passed SlapOS.Eggs.UnitTest-Master.Python2

00:29:07

passed SlapOS.Eggs.UnitTest-Master.Python2

00:10:50

passed SlapOS.Eggs.UnitTest-Master.Python2

00:10:57

passed SlapOS.Eggs.UnitTest-Master.Python2

00:09:44

passed SlapOS.Eggs.UnitTest-Master.Python2

00:09:49

passed SlapOS.Eggs.UnitTest-Master.Python2

00:10:38

passed SlapOS.Eggs.UnitTest-Master.Python3

00:10:54

passed SlapOS.Eggs.UnitTest-Master.Python3

00:19:45

passed SlapOS.Eggs.UnitTest-Master.Python3

00:11:00

passed SlapOS.Eggs.UnitTest-Master.Python3

00:10:32

passed SlapOS.Eggs.UnitTest-Master.Python3

00:11:04

passed SlapOS.Eggs.UnitTest-Master.Python3

00:10:30