hls: Initialize stream_offset before find_stream_info.

find stream info causes reads that may use the offset in their callback
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/hls.c

@@ -527,11 +527,11 @@ static int hls_read_header(AVFormatContext *s)
         if (ret < 0)
             goto fail;
 
+        v->stream_offset = stream_offset;
         v->ctx->ctx_flags &= ~AVFMTCTX_NOHEADER;
         ret = avformat_find_stream_info(v->ctx, NULL);
         if (ret < 0)
             goto fail;
-        v->stream_offset = stream_offset;
         snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
         /* Create new AVStreams for each stream in this variant */
         for (j = 0; j < v->ctx->nb_streams; j++) {