Staging: lustre: Edit switch-case indent

This patch fixes indent as the codingStyle
of the kernel recommends in dir.c
Fix checkpatch.pl error:
ERROR: switch and case should be at the same indent.
Signed-off-by: aybuke ozdemir <aybuke.147@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>