For CBR, keep rate-correction damping factor to 2.

The switch to the rate-correction damping factor
in https://gerrit.chromium.org/gerrit/#/c/67536/ was not conditioned on CBR mode.

Change-Id: I2326704e8ac030a4f7b592dd3fedb94c7dd0644d
diff --git a/test/datarate_test.cc b/test/datarate_test.cc
index 85f4bb6..5785a0a 100644
--- a/test/datarate_test.cc
+++ b/test/datarate_test.cc
@@ -248,9 +248,9 @@
     cfg_.rc_target_bitrate = i;
     ResetModel();
     ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
-    ASSERT_GE(cfg_.rc_target_bitrate, effective_datarate_ * 0.8)
+    ASSERT_GE(cfg_.rc_target_bitrate, effective_datarate_ * 0.9)
         << " The datarate for the file exceeds the target by too much!";
-    ASSERT_LE(cfg_.rc_target_bitrate, effective_datarate_ * 1.3)
+    ASSERT_LE(cfg_.rc_target_bitrate, effective_datarate_ * 1.1)
         << " The datarate for the file missed the target!";
   }
 }
diff --git a/vp9/encoder/vp9_onyx_if.c b/vp9/encoder/vp9_onyx_if.c
index 8a98343..926e91f 100644
--- a/vp9/encoder/vp9_onyx_if.c
+++ b/vp9/encoder/vp9_onyx_if.c
@@ -3443,7 +3443,9 @@
 
   // Post encode loop adjustment of Q prediction.
   if (!active_worst_qchanged)
-    vp9_update_rate_correction_factors(cpi, (cpi->sf.recode_loop) ? 2 : 0);
+    vp9_update_rate_correction_factors(cpi, (cpi->sf.recode_loop ||
+        cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) ? 2 : 0);
+
 
   cpi->last_q[cm->frame_type] = cm->base_qindex;