Fix file open leak

Introduced by commit 87b10676354d10be02864ad615e1e9fe5a2376ab

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index e4671e4..5383dca 100644
--- a/io_u.c
+++ b/io_u.c
@@ -793,8 +793,7 @@
 		if (td->nr_open_files < td->o.open_files &&
 		    td->o.open_files != td->o.nr_files) {
 			f = find_next_new_file(td);
-
-			if (!f || td_io_open_file(td, f))
+			if (!f)
 				return 1;
 
 			goto set_file;