[PATCH] Add fio_assert()

A job must not call assert(), as it wont exit and set thread
state properly.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index 29c23f6..ae92df5 100644
--- a/io_u.c
+++ b/io_u.c
@@ -3,7 +3,6 @@
 #include <string.h>
 #include <signal.h>
 #include <time.h>
-#include <assert.h>
 
 #include "fio.h"
 #include "os.h"
@@ -45,7 +44,8 @@
 		idx = RAND_MAP_IDX(td, f, block);
 		bit = RAND_MAP_BIT(td, f, block);
 
-		assert(idx < f->num_maps);
+		idx = f->num_maps;
+		fio_assert(td, idx < f->num_maps);
 
 		f->file_map[idx] |= (1UL << bit);
 		block++;