kvm: fix python3 support in test

6 jobs for jm
Status Job ID Name Coverage
  External
passed SlapOS.SlapRunner.ResilienceTest-Master

00:26:44

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:19:04

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

05:51:48

passed SlapOS.SlapRunner.ResilienceTest-Master

00:25:33

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master