LU-1994 kernel: kernel 3.6 changes i_dentry/d_alias to hlist

LU-1994 kernel: kernel 3.6 changes i_dentry/d_alias to hlist

kernel 3.6 changes i_dentry/d_alias from list to hlist.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: yang sheng <ys@whamcloud.com>
Change-Id: If05f01fe6fe34225ec24b90bf85eb9e9e80f44f3
Reviewed-on: http://review.whamcloud.com/4385
Tested-by: Hudson
Reviewed-by: Lai Siyao <laisiyao@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>