add support for io_open2

Author: palemieux

libavformat/imfdec.c

@@ -344,6 +344,7 @@ static int open_track_resource_context(AVFormatContext *s,
 
     track_resource->ctx->io_open = s->io_open;
     track_resource->ctx->io_close = s->io_close;
+    track_resource->ctx->io_close2 = s->io_close2;
     track_resource->ctx->flags |= s->flags & ~AVFMT_FLAG_CUSTOM_IO;
 
     if ((ret = ff_copy_whiteblacklists(track_resource->ctx, s)) < 0)