Do not use copytruncate for xcat log rotation

PR #6510 tried to fix missing logs for goconserver, but also added copytruncate to all xcat logs in /var/log/xcat*.log. This is not needed because these logs are written by rsyslog and xcat itself, not goconserver.

The main rsyslog developer does not recommend to use copytruncate for rsyslog: https://serverfault.com/a/901366

For HA setups with logs on NFS etc. copytruncate can be very slow.

xCAT/etc/logrotate.d/xcat

@@ -1,7 +1,6 @@
 /var/log/xcat/*.log {
     missingok
     sharedscripts
-    copytruncate
     delaycompress
     postrotate
         test -f /var/run/rsyslogd.pid && kill -HUP `cat /var/run/rsyslogd.pid 2> /dev/null` 2> /dev/null || true