Fix logrotate for docker-distribution

This used a syntax that was from an old EL and does not work with
newer Fedora with systemctl. Hat tip to misc for helping me figure out
which rpm had the file in it and then what the right syntax was.

roles/docker-distribution/files/syslog-logrotate

@@ -6,7 +6,7 @@
 {
     sharedscripts
     postrotate
-	/bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null || true
+	/usr/bin/systemctl kill -s HUP rsyslog.service >/dev/null 2>&1 || true
     endscript
     daily
     rotate 7