staging: lustre: fix checkpatch error

convert spaces to tab

fix the following error messages from checkpatch.pl

ERROR: code indent should use tabs where possible
WARNING: please, no spaces at the start of a line
Signed-off-by: Anson Jacob <ansonjacob.aj@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>