Update sarg.spec

Corrected small nuances:

*) warning message for being unable to find default font (erroneously
searched under /usr/share/sarg/fonts/DejaVuSans.ttf)

*) default path in sarg.conf for exclude_codes file not valid
(defaulting to /usr/local/sarg/exclude_codes)

*) ONE-SHOT directory/link always empty

All the corrections have been done a lot of time ago (even before the stated 17/10/2012), but I found the time to properly notify them only now, sorry...
On the other hand these are quite well time-tested now ;>

The last addition (hourly cron job) could be left out if you think that the ONE-SHOT should be only manually populated ad-hoc.