Optimize mythconverg table daily

The table can quickly become filled with cruft and inefficient/slow. A cron job to regularly optimize the database can help keep the system running at top shape. This job needs to verify that the system isn't using the table via an xml feed and reschedule as necessary.

From #mythtv:
<sphery> superm1: And, should probably run optimize_mythdb.pl daily, too. :)
<superm1> sphery, something else that will need to check for table locking you would say?
<sphery> I don't on my box and it hasn't caused issues. I run it at a time when I'm unlikely to have recordings. But, if you're already writing the script to check the status, it wouldn't hurt to use it to call optimize_mythdb.pl, too.