LU-3529 osp: init FID client for OSP on MDT.

LU-3529 osp: init FID client for OSP on MDT.

1. Initialize FID client for OSP on MDT.
2. Pull out OSP precreate stuff into a separate structure,
so OSP on MDT does not have to allocate precreate.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I3c4a87e2fbea2a733fc6a4a296a50ba67652aa32
Reviewed-on: http://review.whamcloud.com/7158
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Jenkins
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Tested-by: Oleg Drokin <oleg.drokin@intel.com>