NFSv4: Use the nfs4_state being recovered in _nfs4_opendata_to_nfs4_state()

If we're recovering a nfs4_state, then we should try to use that instead
of looking up a new stateid. Only do that if the inodes match, though.

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