avformat/rtpenc_chain: Use avio_closep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/rtpenc_chain.c

@@ -89,7 +89,7 @@ int ff_rtp_chain_mux_open(AVFormatContext **out, AVFormatContext *s,
 
     if (ret) {
         if (handle && rtpctx->pb) {
-            avio_close(rtpctx->pb);
+            avio_closep(&rtpctx->pb);
         } else if (rtpctx->pb) {
             uint8_t *ptr;
             avio_close_dyn_buf(rtpctx->pb, &ptr);