Revert "services: remove unneeded pidfiles"

This reverts commit 98093edc99.

* * * * *

They aren't needed if systemd starts the service, but what if user
services are used together with cron and liching isn't allowed?

etc/systemd/system/supybot.service

@@ -4,6 +4,7 @@ After=network.target
 
 [Service]
 Type=forking
+PIDFile=/home/bot/botname/botname.pid
 ExecStart=/usr/local/bin/supybot /home/bot/botname/botname.conf --daemon
 ExecReload=/bin/kill -HUP $MAINPID
 Restart=always

etc/systemd/system/znc.service

@@ -4,6 +4,7 @@ After=network.target
 
 [Service]
 Type=forking
+PIDFile=/home/znc/.znc/znc.pid
 ExecStart=/home/znc/.local/bin/znc
 ExecReload=/bin/kill -HUP $MAINPID
 Restart=always