LU-4974 lod: documentation for lod_object.c

LU-4974 lod: documentation for lod_object.c

Comments in Doxygen markup.

Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Signed-off-by: Richard Henwood <richard.henwood@intel.com>
Change-Id: Ib60ae4eb89aeef5c3118f43c0fb640d5820b8b62
Reviewed-on: http://review.whamcloud.com/11022
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Andreas Dilger <andreas.dilger@intel.com>