staging: lustre: reapply an older patch that was reverted

This reapplies part of 9edf0f67 (staging:
lustre: clean up format string usages) as it was reverted in a recent
change to this file.

That proves the big problem of having external trees you have to have
patches flowing back into them from upstream or things break down...

Reported-by: Kees Cook <keescook@chromium.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Peng Tao <bergwolf@gmail.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>