NFSv4: Clean up some shutdown loops

If a SEQUENCE call receives -EIO for a shutdown client, it will retry the
RPC call.  Instead of doing that for a shutdown client, just bail out.

Likewise, if the state manager decides to perform recovery for a shutdown
client, it will continuously retry.  As above, just bail out.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>