fixup! generic_mysql: shorter delays before retries

there was a mistake in 2de4c80f, we
should sleep for the min duration of these two
10 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.SlapRunner.ResilienceTest-Master

00:26:12

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:19:20

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

07:16:14

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

01:44:29

passed SlapOS.SlapRunner.ResilienceTest-Master

00:26:20

passed SlapOS.SlapRunner.ResilienceTest-Master

00:30:46

passed SlapOS.SlapRunner.ResilienceTest-Master

00:29:29

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:09:06

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:08:34

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:06:35