NFSv4.1: Use CLAIM_DELEG_CUR_FH opens when available

Now that we do CLAIM_FH opens, we may run into situations where we
get a delegation but don't have perfect knowledge of the file path.
When returning the delegation, we might therefore not be able to
us CLAIM_DELEGATE_CUR opens to convert the delegation into OPEN
stateids and locks.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>