[vdr] RFC: Set environment variables after switching user (Patch included)

Hello,

depending on the init system and the way, how it is configured, scripts, executed by VDR, either have variables like "HOME" unset or still set to "/root". This is useless for scripts or other external software, called by VDR.

My small patch sets the common environment variables to the correct values for the VDR "runtime user". This fixes many problems with all kinds of external software, called by VDR (ProjectX or even Firefox via "externalplayer" to browse the web on your TV).

Would be great if this small change could still make it into 2.0.

Yours

Manuel Reimer