software/restic: keep using check-secure = 1

This was changed as part of b049c057 (upgrade to slapos.toolbox version
0.123, 2021-07-19), but this is not a slapos.toolbox promise plugin, it's
still an old style promise.
2 jobs for fix/monitoring-promise-username-password in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS.SoftwareReleases.IntegrationTest-Jerome-Python3

06:42:51

failed SlapOS.SoftwareReleases.IntegrationTest-Jerome-WIP

07:35:04