LU-7900 obdclass: lu_object_assign_fid() do not lookup

LU-7900 obdclass: lu_object_assign_fid() do not lookup

as the object is supposed to be new and unique by definition.
this method is used only with OST objects being created on MDT.

Change-Id: I9e641ab208654ea64eb42394a3618c9f30e7d751
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: http://review.whamcloud.com/19081
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>