LU-2789 lod: initialize objects in a detached stripe array

LU-2789 lod: initialize objects in a detached stripe array

Initializing the ldo_stripe member of lod_device in place exposes some
races with attribute setting so instead we use a detached array and
assign that to ldo_stripe once it's complete.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I63d57a21ed7402829d4b3889c1f32d4ddec1f096
Reviewed-on: http://review.whamcloud.com/5422
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>