Bug#747535: systemd-sysv: Ask before installing when upgrading to/installing jessie

[Svante Signell]

Package: systemd-sysv
Version: 204
Severity: serious

When upgrading an old system installing certain packages, like
network-manager and gdm3 systemd is installed changing the init system.
These packages depend on libpam-systemd, which depends on systemd-sysv |
systemd-shim. If systemd-shim is not installed systemd-sysv is, and the
init system changes the default to systemd.

This should be warned about loudly by debconf, since not all users want
to change init system. Of course this should not happen without
informing the user about that during the upgrade.

For new installations the situation is different, systemd is the default
init system. Nevertheless, perhaps even for new installations the user
should be given a choice.