NFS41: map NFS4ERR_LAYOUTUNAVAILABLE to ENODATA

Instead of mapping it to EIO that is a fatal error and
fails application. We'll go inband after getting
NFS4ERR_LAYOUTUNAVAILABLE.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>