LU-3079 kernel: f_vfsmnt replaced by f_path.mnt

LU-3079 kernel: f_vfsmnt replaced by f_path.mnt

In linux 3.9 f_vfsmnt was killed and replaced

commit 182be684784334598eee1d90274e7f7aa0063616
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Thu Jan 24 02:21:54 2013 -0500

    kill f_vfsmnt

    very few users left...

Signed-off-by: Alexey Shvetsov <alexxy@gentoo.org>
Change-Id: I02f595f0b7bbe804c9695d6da2106deb2d17e0ee
Reviewed-on: http://review.whamcloud.com/5899
Tested-by: Hudson
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>