another 10l: forgot to change parent condition as well

Originally committed as revision 21535 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtmpproto.c

@@ -662,7 +662,7 @@ static int get_packet(URLContext *s, int for_header)
     for (;;) {
         RTMPPacket rpkt;
         if ((ret = ff_rtmp_packet_read(rt->stream, &rpkt,
-                                       rt->chunk_size, rt->prev_pkt[0])) != 0) {
+                                       rt->chunk_size, rt->prev_pkt[0])) <= 0) {
             if (ret == 0) {
                 return AVERROR(EAGAIN);
             } else {