Increase QP threshold for H.264 encoder QP based scaling.

BUG=b/30743634

Review-Url: https://codereview.webrtc.org/2272893002
Cr-Commit-Position: refs/heads/master@{#13904}
diff --git a/webrtc/modules/video_coding/utility/quality_scaler.cc b/webrtc/modules/video_coding/utility/quality_scaler.cc
index 8190ef4..c509e84 100644
--- a/webrtc/modules/video_coding/utility/quality_scaler.cc
+++ b/webrtc/modules/video_coding/utility/quality_scaler.cc
@@ -42,8 +42,8 @@
 const int QualityScaler::kLowH264QpThreshold = 32;
 const int QualityScaler::kBadH264QpThreshold = 42;
 #else
-const int QualityScaler::kLowH264QpThreshold = 22;
-const int QualityScaler::kBadH264QpThreshold = 35;
+const int QualityScaler::kLowH264QpThreshold = 24;
+const int QualityScaler::kBadH264QpThreshold = 37;
 #endif
 
 QualityScaler::QualityScaler() : low_qp_threshold_(-1) {}