LU-13260 lov: fix size check when stripe is zero

LU-13260 lov: fix size check when stripe is zero

Set correct max size while stripe is zero.

Fixes: f3f6515562 (LU-8998 lov: add composite layout unpacking)
Signed-off-by: Yang Sheng <ys@whamcloud.com>
Change-Id: I9b76283fcc65f58e3be6adf49f035236687ac85c
Reviewed-on: https://review.whamcloud.com/37623
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>