Improve restorecond systemd unit file

Use Type=forking and pass PIDFile option, this allows better tracking of
the livecycle of the daemon.

Only attempt to start the daemon if selinux is enabled.

Drop After=syslog.target, syslog is socket activated anyway

policycoreutils/restorecond/restorecond.service

@@ -1,12 +1,12 @@
 [Unit]
 Description=Restorecon maintaining path file context
-After=syslog.target
 ConditionPathExists=/etc/selinux/restorecond.conf
+ConditionSecurity=selinux
 
 [Service]
-Type=oneshot
+Type=forking
 ExecStart=/usr/sbin/restorecond
-RemainAfterExit=yes
+PIDFile=/var/run/restorecond.pid
 
 [Install]
 WantedBy=multi-user.target