Video loopback avg_burst_loss_length default parameter fix.

webrtc/video/video_loopback.cc

Index: webrtc/video/video_loopback.cc
diff --git a/webrtc/video/video_loopback.cc b/webrtc/video/video_loopback.cc
index 70a940db5f0151ad63003c802725227390b95845..1622e6ad86c26d68bcc2177545eaf266eca84521 100644
--- a/webrtc/video/video_loopback.cc
+++ b/webrtc/video/video_loopback.cc
@@ -101,7 +101,9 @@ int LossPercent() {
   return static_cast<int>(FLAGS_loss_percent);
 }
 
-DEFINE_int32(avg_burst_loss_length, 1, "Average burst length of lost packets.");
+DEFINE_int32(avg_burst_loss_length,
+             -1,
+             "Average burst length of lost packets.");
 int AvgBurstLossLength() {
   return static_cast<int>(FLAGS_avg_burst_loss_length);
 }