Previously client was not force to use heartbeat. Because we have to be
able to detect dead client in qnetd, heartbeat setting is now forced.
Insted of set_option message, heartbeat is force to exists in init
message. This also means that
QDEVICE_NET_INSTANCE_STATE_WAITING_SET_OPTION_REPLY can be removed and
client is considered as connected after init_reply is received. So
currently, set_option is not used (but implementation of these two
messages still exists).
Signed-off-by: Jan Friesse <jfriesse@redhat.com>