Comment 24 for bug 1821343

Verified according to test case in description for cosmic:

root@cosmic:~# dpkg -l | grep slapd
ii slapd 2.4.46+dfsg-5ubuntu1.2 amd64 OpenLDAP server (slapd)

root@cosmic:~# systemctl status slapd
● slapd.service - LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)
   Loaded: loaded (/etc/init.d/slapd; generated)
  Drop-In: /lib/systemd/system/slapd.service.d
           └─slapd-remain-after-exit.conf
   Active: active (running) since Mon 2019-04-22 20:15:01 UTC; 19s ago
     Docs: man:systemd-sysv-generator(8)
    Tasks: 3 (limit: 4915)
   Memory: 612.7M
   CGroup: /system.slice/slapd.service
           └─2061 /usr/sbin/slapd -h ldap:/// ldapi:/// -g openldap -u openldap -F /etc/ldap/slapd.d

root@cosmic:~# kill -9 2061

root@cosmic:~# systemctl status slapd
● slapd.service - LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)
   Loaded: loaded (/etc/init.d/slapd; generated)
  Drop-In: /lib/systemd/system/slapd.service.d
           └─slapd-remain-after-exit.conf
   Active: inactive (dead) since Mon 2019-04-22 20:15:40 UTC; 4s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 2145 ExecStop=/etc/init.d/slapd stop (code=exited, status=0/SUCCESS)

root@cosmic:~# systemctl cat slapd
# /run/systemd/generator.late/slapd.service
# Automatically generated by systemd-sysv-generator

[Unit]
Documentation=man:systemd-sysv-generator(8)
SourcePath=/etc/init.d/slapd
Description=LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)
Before=multi-user.target
Before=multi-user.target
Before=multi-user.target
Before=graphical.target
After=remote-fs.target
After=network-online.target
Wants=network-online.target

[Service]
Type=forking
Restart=no
TimeoutSec=5min
IgnoreSIGPIPE=no
KillMode=process
GuessMainPID=no
RemainAfterExit=yes
SuccessExitStatus=5 6
ExecStart=/etc/init.d/slapd start
ExecStop=/etc/init.d/slapd stop

# /lib/systemd/system/slapd.service.d/slapd-remain-after-exit.conf
[Service]
Type=forking
RemainAfterExit=no