LU-1303 lod: object create to create underlying objects

LU-1303 lod: object create to create underlying objects

and generate LOV EA for just created striping. the policies
choosing specific OSPs to use in the striping is in the
subsequent patch.

Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Change-Id: I2675dd3e2ba4455b2b0daaf4aa7af30b910e9a75
Reviewed-on: http://review.whamcloud.com/4057
Reviewed-by: wangdi <di.wang@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Mike Pershin <tappro@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>