Set local SSRC for VideoReceiveStream.

As a bonus, also removes GenerateRandomSsrc, which only worked on sender
configs. There's no point to generate random SSRCs in tests.

BUG=2691
R=mflodman@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/4689004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@5201 4adac7df-926f-26a2-2b94-8c16560cd09d
11 files changed