Silence gcc 4.6 warnings

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/filesetup.c b/filesetup.c
index 1350857..799202f 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -504,7 +504,7 @@
 
 	if (!from_hash && f->fd != -1) {
 		if (add_file_hash(f)) {
-			int ret;
+			int fio_unused ret;
 
 			/*
 			 * OK to ignore, we haven't done anything with it