LU-6142 uapi: Get rid of lustre_fid typedef

LU-6142 uapi: Get rid of lustre_fid typedef

Replace it with struct lu_fid. Update the userland code and man
pages to reflect this change.

Linux-commit: d8f6bc9a53f97d1ea4b2b955672904338643308b

Test-Parameters: trivial

Change-Id: I0b7e0770dd9da9bdac55c02c2ec98aea7cea7100
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Reviewed-on: https://review.whamcloud.com/29849
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>