net/virtio-user: do not assume features are negotiated

net/virtio-user: do not assume features are negotiated

According to the virtio spec, ACK and DRIVER status bits should be set
before feature negotiation.

However, until the protocol features are negotiated, the driver does not
know if the device actually supports those vhost-user messages.
Therefore, until FEATURES_OK is set, the GET/SET_STATUS messages should
not be sent.

Fixes: 57912824615f ("net/virtio-user: support vhost status setting")
Cc: stable@dpdk.org
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>