[mythtv] Untunable channels on multirec

[mythtv at longhome.co.uk]

I think I've found a bug on multirec. If I exit from a channel (maybe to
watch a recording), and then go back to live TV after that channel has
'closed' (ie nothing is broadcasting). It never retunes to the channel
(doesn't even display the mheg 'This channel is closed' screen), and if I
try and tune to a different channel, I get "An error occurred while trying
to display video". The only way I could get back to a tunable channel was by
editing the start channel in the cardinput table. 

Nothing obvious in the logs. I'll try upping the logging.

Martin