[vdr] Odd shutdown

[Lauri Tischler <lauri.tischler@efore.fi>]

I was watching channel 3 on DVB-T budjetcard.
Hit the POWER button on remote.
The VDR changed to channel 55 on DVB-S card and
displayed the shutdown banner.
I hit some key and VDR switched back to channel 3
It appears the VDR in this case switches to the last used
channel (55) on DVB-S

This switch sometimes also happens when switching between
channels on DVB-T.
Switch from 3 to 4 and between you get quick peek on
some DVB-S channel.
My channels 1-11 are on DVB-T, 12 - 62 on DVB-S