LU-2941 llite: Delaying creation of client side proc entries.

LU-2941 llite: Delaying creation of client side proc entries.

In client_common_fill_super() proc entries are created before
before cl_sb_init() and therefore lu_site is not allocated resulting
in client crash when tried reading lu_site stats.
Delaying creation of proc entries after creation of all required data
structures fixed the problem.

Signed-off-by: Gaurav Mahajan <gmahajan@ddn.com>
Change-Id: Id9fc9adc3ce043c691e2d26b85c4bd1917444144
Reviewed-on: http://review.whamcloud.com/6852
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>