service_pause and service_resume do not work as documented on systemd

The documentation for service_pause() is documented as:

"Pause a system service. Stop it, and prevent it from starting again at boot."

This is not accurate, because service_pause stops the service and prevents it from starting at all, both on boot and when called manually.

Similarly, service_resume() is documented as:

"Resume a system service. Reenable starting again at boot. Start the service."

However, if a service is disabled, running service_pause() and service_resume() will not cause the service to be enabled at boot.

This behaviour is due to service_pause/resume using systemctl mask/unmask rather than disable/enable as it does for other init systems.