Initialize CodecInst structs in test_api_audio.cc.

Fixes errors detected by DrMemory on Windows.

BUG=2382
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2228004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4764 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed