openfiles fix

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/init.c b/init.c
index 7cf5cab..a6d8bae 100644
--- a/init.c
+++ b/init.c
@@ -811,7 +811,7 @@
 	if (td->filename)
 		td->nr_uniq_files = 1;
 	else
-		td->nr_uniq_files = td->nr_files;
+		td->nr_uniq_files = td->open_files;
 
 	if (td->filetype == FIO_TYPE_FILE || td->filename) {
 		char tmp[PATH_MAX];