asfdec: Remove dead code from asf_read_close().

libavformat/asfdec.c

@@ -1132,12 +1132,8 @@ static void asf_reset_header(AVFormatContext *s)
 
 static int asf_read_close(AVFormatContext *s)
 {
-    int i;
-
     asf_reset_header(s);
-    for(i=0;i<s->nb_streams;i++) {
-        AVStream *st = s->streams[i];
-    }
+
     return 0;
 }