LU-4974 lod: add comments for lod_pool.c functions

LU-4974 lod: add comments for lod_pool.c functions

Fix up GPL header block to reference proper GPLv2 license URL.
Remove mention of contacting Sun, since they don't exist anymore.

Add introductory comment block for the lod_pool.c file.
Add function comment blocks to all functions in the lod_pool.c file.

Minor cleanup of variable and function names for consistency, since
they affect the code comments.  Other code changes for issues found
during commenting will be in separate follow-on patches.

This patch specifically excludes changing cfs_list_t->struct list_head
and similar cleanups, since they would touch too many lines of code in
the patch to review easily.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Id914f54bd67138d36041b5867541703a5a500c1e
Reviewed-on: http://review.whamcloud.com/10145
Tested-by: Jenkins
Reviewed-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>