Define stubs for sequence args and res data structures and embed
them in all other nfs4 and nfs41 xdr types.  They are needed for
sending any op in a nfs41 compound rpc.

Signed-off-by: Andy Adamson<andros@netapp.com>
[moved new args/res definitions away, to where they're first used]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>