Stop DirectTransports in VideoSendStreamTests.

Prevents racy packet delivery during or after Call destruction.

BUG=
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/3099005

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@5049 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed