kset: move /sys/slab to /sys/kernel/slab

/sys/kernel is where these things should go.
Also updated the documentation and tool that used this directory.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index d17f324..dcf8bcf 100644
--- a/Documentation/vm/slub.txt
+++ b/Documentation/vm/slub.txt
@@ -63,7 +63,7 @@
 possible to enable debugging manually when the kernel is up. Look at the
 contents of:
 
-/sys/slab/<slab name>/
+/sys/kernel/slab/<slab name>/
 
 Look at the writable files. Writing 1 to them will enable the
 corresponding debug option. All options can be set on a slab that does