LU-1301 lu: local objects library

LU-1301 lu: local objects library

set of functions working on top of OSD API to create/access
local objects by name.
the library maintains own top device to be able to work in
multi-service environment (mds + mgs).

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I26cc47b866bb0925be4f4419ac663a1d42520e02
Reviewed-on: http://review.whamcloud.com/3665
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>