Disable frame dropping by default

This is not the behavior that most users expect.

Change-Id: I226126ea400c22cf1f7918e80ea7fe0771c569cb

vp8/vp8_cx_iface.c

@@ -1024,7 +1024,7 @@ static vpx_codec_enc_cfg_map_t vp8e_usage_cfg_map[] =
 
         0,                  /* g_lag_in_frames */
 
-        70,                 /* rc_dropframe_thresh */
+        0,                  /* rc_dropframe_thresh */
         0,                  /* rc_resize_allowed */
         60,                 /* rc_resize_down_thresold */
         30,                 /* rc_resize_up_thresold */