[mythtv] fixes to mythburn.py

[John Pilkington]

Hi:  It's my impression that dev interest in MythArchive is almost 
extinct.  I suggest that you just open a ticket with a unified diff of 
your changes and the comments you have already made.  It gets tedious to 
keep things updated if you don't use something like git, but there 
haven't been many changes here recently, and at least interested users 
will have access to what you have done.

Ignore this if you get any more conventional or 'official' replies.

John P