[PATCH] iolog: fix disk stats issue

The disk util structure of the td does not initialized when
iolog replay, and the disk stats is the initial value.

Signed-off-by: yonggang.yyg <yygcode@gmail.com>

iolog.c

@@ -588,6 +588,8 @@ int init_iolog(struct thread_data *td)
  if (ret)
  td_verror(td, EINVAL, "failed initializing iolog");
 
+ init_disk_util(td);
+
  return ret;
 }