staging/lustre: Properly reference kthread_run instead of cfs_daemonize

cfs_daemonize is long gone and replaced by a proper call to kthread_run,
so update the comment to reflect that fact.

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