avformat/rtsp: Clear reply in every iteration in ff_rtsp_connect()

Fixes: Infinite loop

Found-by: Michael Hanselmann <public@hansmi.ch>
Reviewed-by: Michael Hanselmann <public@hansmi.ch>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 0b50f27635)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/rtsp.c

@@ -1643,7 +1643,7 @@ int ff_rtsp_connect(AVFormatContext *s)
     char tcpname[1024], cmd[2048], auth[128];
     const char *lower_rtsp_proto = "tcp";
     int port, err, tcp_fd;
-    RTSPMessageHeader reply1 = {0}, *reply = &reply1;
+    RTSPMessageHeader reply1, *reply = &reply1;
     int lower_transport_mask = 0;
     int default_port = RTSP_DEFAULT_PORT;
     char real_challenge[64] = "";
@@ -1672,6 +1672,7 @@ int ff_rtsp_connect(AVFormatContext *s)
     rt->lower_transport_mask &= (1 << RTSP_LOWER_TRANSPORT_NB) - 1;
 
 redirect:
+    memset(&reply1, 0, sizeof(reply1));
     /* extract hostname and port */
     av_url_split(proto, sizeof(proto), auth, sizeof(auth),
                  host, sizeof(host), &port, path, sizeof(path), s->filename);