Non-systemd based Debians don't periodically recontextualize on vCenter

[vholer]

Periodic recontextualization check for #185 doesn't happen on Debian-based systems which don't use systemd (e.g., Devuan), because there is a single .deb package for all Debian-like systems which contains only a systemd timer one-context-reconfigure.timer, but not a cron schedule (/etc/cron.d/one-context-reconfigure). Solution might be to

• distribute both systemd timer and cron schedule in a single Debian pakage,
• inside the cron-schedule, check and run only if timer is not active.

Remove skip in tests when fixed: https://github.com/OpenNebula/development/blob/208bde38f0052c05d5eecc738509382b0ebff476/readiness/spec/context/linux/network.rb#L250