Bug#768456: init-system-helpers: deb-system-invoke starts disabled systemd service on package upgrade

[Didier Roche]

Package: init-system-helpers
Version: 1.21
Severity: normal

Dear Maintainer,

deb-system-invoke starts disabled systemd services (and so, in case
of systemd only services), when there is no init script.

As discuss on #debian-systemd, we can add some conditions to start the job
on deb-system-invoke [restart|start], during package upgrade:
- deb-system-invoke start <unit> don't do anything on systemd if the
   service is disabled.
- deb-system-invoke restart <unit> only restart a disabled service if
   if the daemon was already running (forced by the admin).

-- System Information:
Debian Release: jessie/sid
   APT prefers vivid-updates
   APT policy: (500, 'vivid-updates'), (500, 'vivid-security'), (500, 
'vivid')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-24-generic (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages init-system-helpers depends on:
ii  perl  5.20.1-2

init-system-helpers recommends no packages.

init-system-helpers suggests no packages.

-- no debconf information