[vdr] Use a string for options if value zero

[Klaus Schmidinger]

Andreas Brachold wrote:
> Hi,
> 
> here for vdr-1.3.47 as small enhance, 
> use strings for options if value zero.
> 
> * Min. user inactivity (min) => none
> * EPG scan timeout (h) => none
> 
> Maybe is a other text better descriptive,
> like "off" or "inactive"

This would most likely introduce new I18N strings, which
I'd like to avoid at the moment.

Maybe in version 1.5.x...

Klaus