slub: fix a possible memory leak

Memory allocated by kstrdup should be freed,
when kmalloc(kmem_size, GFP_KERNEL) is failed.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
slub: remove unused argument of init_kmem_cache_node()

We don't use the argument since commit 3b89d7d881a1dbb4da158f7eb5d6b3ceefc72810
('slub: move min_partial to struct kmem_cache'), so remove it

Signed-off-by: Joonsoo Kim <js1304@gmail.com>