media/video: disable key frame SIP-INFO request

If a keyframe request is never answered, a timeout is reached
and the call failed.
As keyframe requests are transmit over UDP, they are too easily dropped,
on connection like wifi.

This feature is not mandatory for communication and until we found
a better solution this patch disables the request.

Change-Id: I3d5e8d0e3d0119db52fbfc0f37ce2949224b1806
Tuleap: #167

src/media/video/video_rtp_session.cpp

@@ -130,7 +130,10 @@ void VideoRtpSession::startReceiver()
         receiveThread_.reset(
             new VideoReceiveThread(callID_, receive_.receiving_sdp)
         );
+        /* ebail: keyframe requests can lead to timeout if they are not answered.
+         * we decided so to disable them for the moment
         receiveThread_->setRequestKeyFrameCallback(&SIPVoIPLink::enqueueKeyframeRequest);
+        */
         receiveThread_->addIOContext(*socketPair_);
         receiveThread_->startLoop();
     } else {