staging/lustre/llite: move /proc/fs/lustre/llite/stats_track* to sysfs

Move stats_track_pid, stats_track_ppid and stats_track_gid  files
from /proc/fs/lustre/llite/* to /sys/fs/lustre/llite/*/

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>