software/slapos-testing: add jq, sed and grep in PATH

This is used by caucase.sh test
8 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.Eggs.UnitTest-Master.Python2

00:11:16

passed SlapOS.Eggs.UnitTest-Master.Python3

00:11:56

passed SlapOS.SlapRunner.ResilienceTest-Master

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:25:31

passed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

06:58:15

passed SlapOS.Eggs.UnitTest-Master.Python2

00:11:22

passed SlapOS.Eggs.UnitTest-Master.Python3

00:12:35