LU-5234 llite: restore newer kernel support for ll_read_dir

LU-5234 llite: restore newer kernel support for ll_read_dir

During the merger of the patch for LU-4906 the support for
newer kernels was removed in the new code. This patch
restores this functionality so RHEL7 and SuSE12 clients can
function again.

Change-Id: Ieea4fb23cd644b2d6ce998cfdba8e0e15e481fc5
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Reviewed-on: http://review.whamcloud.com/10761
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>