install-script: Follow FHS rules

systemd/smartdns.service.in

@@ -1,17 +1,17 @@
 [Unit]
 Description=smart dns server
 After=network.target 
+StartLimitBurst=0
+StartLimitIntervalSec=60
 
 [Service]
 Type=forking
-PIDFile=/var/run/smartdns.pid
-EnvironmentFile=/etc/default/smartdns
-ExecStart=/usr/sbin/smartdns $SMART_DNS_OPTS
+PIDFile=@RUNSTATEDIR@/smartdns.pid
+EnvironmentFile=@SYSCONFDIR@/default/smartdns
+ExecStart=@SBINDIR@/smartdns -p @RUNSTATEDIR@/smartdns.pid $SMART_DNS_OPTS 
 KillMode=process
 Restart=always
 RestartSec=2
-StartLimitBurst=0
-StartLimitIntervalSec=60
 
 [Install]
 WantedBy=multi-user.target