slub: another slabinfo fix

The slab manipulation functions should not be triggered by slabs that
are unresovable in the subset of slabs selected on the command line.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>