Respect client request for not getting a delegation in NFSv4.1
Appropriately return delegation "type" NFS4_OPEN_DELEGATE_NONE_EXT
and WND4_NOT_WANTED reason.

[nfsd41: add missing break when encoding op_why_no_deleg]
Signed-off-by: NBenny Halevy <bhalevy@tonian.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>