test: update to use new object system

test/json-read.c

@@ -26,7 +26,7 @@ int main(int argc, const char **argv)
 	b_serial_ctx *ctx;
 	b_serial_ctx_create(&ctx);
 
-	b_dsref *data;
+	b_object *data;
 	b_status status = b_serial_ctx_deserialise(
 		ctx, B_SERIAL_FORMAT_JSON, src_stream, &data, 0);
 	if (!B_OK(status)) {
@@ -34,10 +34,10 @@ int main(int argc, const char **argv)
 		return -1;
 	}
 
-	b_to_string(B_DSREF(data), b_stdout);
+	b_object_to_string(data, b_stdout);
 	b_stream_write_char(b_stdout, '\n');
 
-	b_release(data);
+	b_object_unref(data);
 	b_serial_ctx_destroy(ctx);
 
 	return 0;