fix team chat beep sound
There are two beep sounds :
* General chat and (**talk.wav**)
* team messages (**talk2.wav**)
These should not be converted to **ogg**, otherwise the engine does not find **talk2.wav**.
See: https://gitlab.com/xonotic/darkplaces/blob/div0-stable/cl_parse.c#L517
This causes that the beep sound for general chat is used for team messages, too.
The script *cached_converter.sh* already tries excludes them (But uses wrong path.)
See merge request !15