This fixes the broken duplicate slab name check in
kmem_cache_sanity_check() that has been repeatedly reported (as recently
as today against Fedora rawhide).  Pekka seemed to have it staged for a
late 3.15-rc in his 'slab/urgent' branch but never sent a pull request,
see: https://lkml.org/lkml/2014/5/23/648
Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux into for-3.16-rcX