LU-1531 mdt: Check non-normalised fid.

LU-1531 mdt: Check non-normalised fid.

Apply fid checking in a manner similar to mdt_fid2path processing.

IGIF FIDs are checked to ensure correct behavior for upgraded
1.8 filesystems.

Signed-off-by: Richard Henwood <richard.henwood@intel.com>
Change-Id: Iea7ebfda8a31915b9d4fe2959773c9312b087485
Reviewed-on: http://review.whamcloud.com/4255
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mike Pershin <tappro@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>