Doc: man: refer to the modern run state directory /run

Author: gao-yan

man/sbd.8.pod.in

@@ -242,7 +242,7 @@ Defaults to I<enabled>.
 This can be used to override the default watchdog device used and should not
 usually be necessary.
 
-=item B<-p> F</var/run/sbd.pid>
+=item B<-p> F</run/sbd.pid>
 
 This option can be used to specify a pidfile for the main sbd process.