message: Fix a crash when connecting Firefox to Erizo
diff: @@ -40,7 +40,6 @@ std::unique_ptr<RemoteBitrateEstimator> RemoteBitrateEstimatorPicker::pickEstima
  BandwidthEstimationHandler::BandwidthEstimationHandler(std::shared_ptr<RemoteBitrateEstimatorPicker> picker) :
  connection_{nullptr}, clock_{webrtc::Clock::GetRealTimeClock()},
  picker_{picker},
  - rbe_{picker_->pickEstimator(false, clock_, this)},
  using_absolute_send_time_{false}, packets_since_absolute_send_time_{0},
  min_bitrate_bps_{kMinBitRateAllowed},
  bitrate_{0}, last_send_bitrate_{0}, last_remb_time_{0},
  @@ -72,6 +71,7 @@ void BandwidthEstimationHandler::notifyUpdate() {
  return;
  }
  updateExtensionMaps(processor_.getVideoExtensionMap(), processor_.getAudioExtensionMap());
  + pickEstimator();
  initialized_ = true;
  }
  @@ -127,7 +127,7 @@ void BandwidthEstimationHandler::updateExtensionMap(bool is_video, std::array<RT
  }
  void BandwidthEstimationHandler::read(Context *ctx, std::shared_ptr<dataPacket> packet) {
  - if (!running_) {
  + if (initialized_ && !running_) {
  process();
  running_ = true;
  }
  