install tries to run a "start" command and uninstall tries to run a "stop" command

On installing the plugin I see this - note the error on the last line:

```
doylands@HGRSDELTCG30106:~$ sudo dpkg -i session-manager-plugin.deb
Selecting previously unselected package session-manager-plugin.
(Reading database ... 84984 files and directories currently installed.)
Preparing to unpack session-manager-plugin.deb ...
Preparing for install
/var/lib/dpkg/tmp.ci/preinst: 4: stop: not found
Unpacking session-manager-plugin (1.2.398.0-1) ...
Setting up session-manager-plugin (1.2.398.0-1) ...
Starting session-manager-plugin
/var/lib/dpkg/info/session-manager-plugin.postinst: 4: start: not found
```

Looking at ```/var/lib/dpkg/info/session-manager-plugin.postinst``` it shows this:

```
echo "Starting session-manager-plugin"
if [ $(cat /proc/1/comm) = init ]
then
start session-manager-plugin || true
elif [ $(cat /proc/1/comm) = systemd ]
then
systemctl enable session-manager-plugin
systemctl start session-manager-plugin
systemctl daemon-reload
fi
if [ -f /usr/local/bin/session-manager-plugin ]
then
rm /usr/local/bin/session-manager-plugin
fi
ln -s /usr/local/sessionmanagerplugin/bin/session-manager-plugin /usr/local/bin/session-manager-plugin
```

It is trying to run a ```start``` command as my system is using ```init```, but this does not exist.

Same sort of issue happens on uninstall due to this file containing a ```stop``` command:

```/var/lib/dpkg/info/session-manager-plugin.prerm```