nfs41: use nfs4_fs_locations_res

In preparation for nfs41 sequence processing.

Signed-off-by: Andy Admason <andros@netapp.com>
[find nfs4_fs_locations_res]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>