audioproc: Now also writes to output file in simulation mode

After changing to use wav as default file format no output was written in simulation mode.

BUG=3359
TESTED=locally
R=aluebs@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25639004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7286 4adac7df-926f-26a2-2b94-8c16560cd09d