Add ni_debug_timer calls

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Convert DHCP4 fsm state to enum to catch all states

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Replace if lists with switch to catch all DHCP4 states

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Handle defer-timeout (DHCLIENT_WAIT_AT_BOOT)

Signed-off-by: Olaf Hering <olaf@aepfle.de>