LU-2118 mdt: fetch parent fid if requested

LU-2118 mdt: fetch parent fid if requested

open-by-fid replay needs this functionality to use correct parent
and appropriate default striping.

Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Change-Id: I8aa618f98f7a7dbbcf32f3407fa89c79a8b98d83
Reviewed-on: http://review.whamcloud.com/4503
Reviewed-by: Mike Pershin <tappro@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>