ffserver: remove usage of deprecated rc_eq option

The private codec option will be used instead when available.

fftools/ffserver_config.c

@@ -291,11 +291,9 @@ static void add_codec(FFServerStream *stream, AVCodecContext *av,
         }
 
         if (!av_dict_get(recommended, "rc_eq", NULL, 0)) {
-            av->rc_eq = av_strdup("tex^qComp");
             av_dict_set(&recommended, "rc_eq", "tex^qComp", 0);
             WARNING("Setting default value for video rate control equation = "
-                    "%s. Use NoDefaults to disable it.\n",
-                    av->rc_eq);
+                    "tex^qComp. Use NoDefaults to disable it.\n");
         }
         if (!av_dict_get(recommended, "maxrate", NULL, 0)) {
             av->rc_max_rate = av->bit_rate * 2;