slub: Fix a crash during slabinfo -v

Commit f7cb1933 ("SLUB: Pass active
and inactive redzone flags instead of boolean to debug functions")
missed two instances of check_object(). This caused a lot of warnings
during 'slabinfo -v' finally leading to a crash:

  BUG ext4_xattr: Freepointer corrupt
  ...
  BUG buffer_head: Freepointer corrupt
  ...
  BUG ext4_alloc_context: Freepointer corrupt
  ...
  ...
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffff810a291f>] file_sb_list_del+0x1c/0x35
  PGD 79d78067 PUD 79e67067 PMD 0
  Oops: 0002 [#1] SMP
  last sysfs file: /sys/kernel/slab/:t-0000192/validate

This patch fixes the problem by converting the two missed instances.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>