RT: reset overshoot detection flag on every frame.

It'll remain off for key frame.

BUG=b/160813654

Change-Id: I4893bc899ca05166ed25cec74f80d88b6c1849ff
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index 82d25a5..29e1808 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -691,6 +691,7 @@
   sf->rt_sf.use_nonrd_pick_mode = 0;
   sf->rt_sf.use_real_time_ref_set = 0;
   sf->rt_sf.check_scene_detection = 0;
+  sf->rt_sf.overshoot_detection_cbr = NO_DETECTION;
   sf->tx_sf.adaptive_txb_search_level = 1;
   sf->tx_sf.intra_tx_size_search_init_depth_sqr = 1;
   sf->tx_sf.model_based_prune_tx_search_level = 1;