slapos_parameter_editor: stop crashing early, as it occurs too often and make the panel unusable

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

01:55:42

passed SlapOS.Eggs.UnitTest-Master.Python2

00:18:59

failed SlapOS.Eggs.UnitTest-Master.Python3

00:17:08

failed SlapOS.SoftwareReleases.IntegrationTest-TestRunner1

09:18:27

failed SlapOS-Master.UnitTest-Master

02:05:34

failed SlapOS-Master.UnitTest-Master

01:51:45

passed SlapOS.Eggs.UnitTest-Master.Python2

00:19:56

failed SlapOS.Eggs.UnitTest-Master.Python2

00:16:15

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:18

passed SlapOS.Eggs.UnitTest-Master.Python2

00:24:48

failed SlapOS.Eggs.UnitTest-Master.Python3

00:19:19

failed SlapOS.Eggs.UnitTest-Master.Python3

00:19:58

failed SlapOS.Eggs.UnitTest-Master.Python3

00:23:34

failed SlapOS.Eggs.UnitTest-Master.Python3

00:24:14

canceled SlapOS.SoftwareReleases.IntegrationTest-TestRunner1