Bug#863227: system-config-printer: applet.py does not exit with session

[Vladimir K]

Package: system-config-printer
Version: 1.5.7-3
Severity: normal

Dear Maintainer, printing applet (started in openbox session via XDG autostart)
does not exit upon logout from openbox session. This leaves a process:

     /usr/bin/python3 /usr/share/system-config-printer/applet.py

and a dangling session visible via loginctl list-sessions.

-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (900, 'testing'), (400, 'unstable'), (300, 'experimental')
Architecture: amd64
 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages system-config-printer depends on:
ii  gir1.2-gdkpixbuf-2.0          2.36.5-2
ii  gir1.2-glib-2.0               1.50.0-1+b1
ii  gir1.2-gtk-3.0                3.22.11-1
ii  gir1.2-notify-0.7             0.7.7-2
ii  gir1.2-packagekitglib-1.0     1.1.5-2
ii  gir1.2-pango-1.0              1.40.5-1
ii  python3-cups                  1.9.73-1
ii  python3-cupshelpers           1.5.7-3
ii  python3-dbus                  1.2.4-1+b1
ii  python3-gi                    3.22.0-2
pn  python3:any                   <none>
ii  system-config-printer-common  1.5.7-3

Versions of packages system-config-printer recommends:
pn  cups-pk-helper              <none>
pn  python3-smbc                <none>
pn  system-config-printer-udev  <none>

Versions of packages system-config-printer suggests:
pn  gnome-software  <none>

-- no debconf information