LU-339 use new aops for kernel >= RHEL5.4

LU-339 use new aops for kernel >= RHEL5.4

for RHEL5 kernel, from >= 5.4 both old and new aops interface are
supported, and a flag MS_HAS_NEW_AOPS is used to mark wheather a
filesystem supports it. Enable it for lustre by default, and this
will increase single thread IO perf > 5% due to kernel
implementation.

Signed-off-by: Lai Siyao <laisiyao@whamcloud.com>
Change-Id: I8f0bfb1c4eea39275cb22c52e30310dcad41db14
Reviewed-on: http://review.whamcloud.com/570
Tested-by: Hudson
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>