The frontend may not send the get_inflight_fd and
set_inflight_fd although we negotiate the protocol
feature. When we meet this situation just return OK.
Fixes: ad0a4ae491fe ("vhost: checkout resubmit inflight information")
Cc: stable@dpdk.org
Signed-off-by: Jin Yu <jin.yu@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>