LU-1301 mgs: osd api based setup

LU-1301 mgs: osd api based setup

Add new mgs_fs_setup() and mgs_fs_cleanup() routines to
initialize local objects using OSD API.  The corresponding old
mgs_fs_setup() and mgs_fs_cleanup() routines are still called
so that lvfs-based functions still work during the transition.

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: Ib4bb83e6f8b3e5146363197b9793a810a9242b19
Reviewed-on: http://review.whamcloud.com/3675
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Mike Pershin <tappro@whamcloud.com>