Comment 2 for bug 1385817

Your upgrade log shows:

Paramétrage de initscripts (2.88dsf-41ubuntu18) ...
Installation de la nouvelle version du fichier de configuration /etc/init.d/ondemand ...
insserv: warning: script 'K01vpnagentd_init' missing LSB tags and overrides
insserv: warning: script 'cron' missing LSB tags and overrides
insserv: Default-Start undefined, assuming empty start runlevel(s) for script `cron'
insserv: Default-Stop undefined, assuming empty stop runlevel(s) for script `cron'
insserv: warning: script 'vpnagentd_init' missing LSB tags and overrides
[...]
insserv: Starting vpnagentd_init depends on grub-common and therefore on system facility `$all' which can not be true!
insserv: exiting now without changing boot order!
update-rc.d: error: insserv rejected the script header
dpkg: error processing package initscripts (--configure):
 le sous-processus script post-installation installé a retourné une erreur de sortie d'état 1

With this release of Ubuntu, we require init scripts to declare LSB dependencies in a pseudoheader, so that insserv is able to calculate a dependency tree for them. This is an unfortunate side-effect of the longer-term transition between upstart and systemd.

To fix your particular problem, it should suffice for you to add the following lines to the top of your local /etc/init.d/vpnagentd_init script (below the first line):

### BEGIN INIT INFO
# Required-Start: $remote_fs
# Required-Stop: $remote_fs
### END INIT INFO

It's not clear to me that we can do anything further to mitigate this problem on upgrade, but we should certainly make sure that it gets documented in the release notes.