NFS: Change nfs4_setup_sequence() to take an nfs_client structure

I want to have all callers use this function, rather than calling the
NFS v4.0 and v4.1 versions directly.  This includes pNFS, which only has
access to the nfs_client structure in some places.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>