lavf/hls: do not transfer custom IO flag

See 0dcac9c3

libavformat/hls.c

@@ -1761,7 +1761,7 @@ static int hls_read_header(AVFormatContext *s)
         }
         pls->ctx->pb       = &pls->pb;
         pls->ctx->io_open  = nested_io_open;
-        pls->ctx->flags   |= s->flags;
+        pls->ctx->flags   |= s->flags & ~AVFMT_FLAG_CUSTOM_IO;
 
         if ((ret = ff_copy_whiteblacklists(pls->ctx, s)) < 0)
             goto fail;