b=10968

i= Nathan, Kalpak

1) merged vfs_stats to stats file.
2) changed stats file to be used under differebt modes (all process, specific GID, PID or PPID)
3) replaced ll_lock by new locks for ll_rw_stats_tally.
4) Turn on collection of statistics ll_rw_stats_tally only when a special
character is echoed into any of the extents_stats, extents_stats_per_process,
offset_stats files.