LU-1286 obdclass: oops in lprocfs_remove_nolock

LU-1286 obdclass: oops in lprocfs_remove_nolock

Move lov /proc entry cleanup from lov_precleanup to
lov_cleanup, so the lov proc entry will be removed after
the pool has been removed, otherwise it will
cause oops during pool proc entry deletion.

Signed-off-by: Di Wang <di.wang@whamcloud.com>
Change-Id: I1d1b03d02348caaa1e421aa1de1535c8cf0ba3f4
Reviewed-on: http://review.whamcloud.com/2450
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>