slapos_accounting: Minor fixup

10 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS-Master.UnitTest-Master

01:08:32

passed SlapOS.Eggs.UnitTest-Master.Python2

00:08:08

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:08

failed SlapOS.Eggs.UnitTest-Master.Python2

00:28:16

passed SlapOS.Eggs.UnitTest-Master.Python2

00:17:54

passed SlapOS.Eggs.UnitTest-Master.Python2

00:31:29

failed SlapOS.Eggs.UnitTest-Master.Python2

00:18:45

passed SlapOS.Eggs.UnitTest-Master.Python3

00:08:56

passed SlapOS.Eggs.UnitTest-Master.Python3

00:09:53

passed SlapOS.Eggs.UnitTest-Master.Python3

00:09:16