component/nxdtest: v↑ (properly cancel on SIGTERM/SIGINT)

This upgrade teaches nxdtest to properly cancel test run and test job
when it receives SIGTERM or SIGINT.

See nxdtest@6f75fa90...56e52da6 for details.

/reviewed-by @jerome
/reviewed-on !1121
5 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed Cloudooo.UnitTest-Master

00:09:22

passed SlapOS.Eggs.UnitTest-Master.Python2

00:12:44

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:37

passed SlapOS.SlapRunner.ResilienceTest-Master

00:23:50

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

01:29:39