NFSv4.1: nfs4_opendata_check_deleg needs to handle NFS4_OPEN_CLAIM_DELEG_CUR_FH

We need to warn against broken NFSv4.1 servers that try to hand out
delegations in response to NFS4_OPEN_CLAIM_DELEG_CUR_FH.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>