Fix purging of log files

[helioz2000]

Line 45 comment indicates files to be purged if they are older than 2 days. According to "man find" the option "-mtime +1" will provide this functionality (see "-atime" example in "man find").

[MW0MWZ]

Did you check to see if this is working? Remember that this is operating along side of log rotate too.

[helioz2000]

@MW0MWZ - As far as I can ascertain logrotate is not affecting any files in /var/log/pi-star/ .
Please correct me if I'm wrong but if logrotate was to handle any pi-star log files I'd expect /etc/logrotate.d/ to contain a pi-star config entry.
As far as I can see, /usr/local/sbin/pistar-daily.cron is the only script which handles log files located in /var/log/pi-star/. I also note that the same script removes all files in /var/log/ - these log files are handled by /etc/logroate.d/rsyslog which compresses and rotates them daily, keeping 2 copies before deleting. However, /usr/local/sbin/pistar-daily.cron will actually delete those files and therefore render logrotate useless for /var/log/.
The above analysis is a bit more complex than the intent of this pull request .... I was simply referring to the mismatch between the comment line ("Purge the logs older than 2 days") and the "-mtime +0" parameter. man page for find states "-mtime +1" results in files modified more than 2 days ago (as explained under -atime).
It comes down to the intent of pi-star log file handling .... the way it currently works (-mtime +0) will leave the "current" log file (the one that's being written to by the process) and one completed log (old) file, any files before that are deleted.
Whereas "-mtime +1" will leave 2 completed log files in addition to the current log file.

IMHO logrotate would be a more flexibility solution for pi-star log files.