staging/lustre: Fix unnecessary parentheses around variables

This patch fixes all checkpatch occurences of
"CHECK: Unnecessary parentheses around xxx"
in Lustre code.

Signed-off-by: Emoly Liu <emoly.liu@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>