Now that the state machine is known to work, we'd better only report
state changes. So this is the new output for the whole cycle
when a fiber is plugged (including kernel messages on the console):

   wri3: Link up, lpa 0x41a0.
   device wri3 entered promiscuous mode
   FSM: wri3: down -> sniff
   device wri3 left promiscuous mode
   recvfrom(wri3): 0800-90e2ba456c6b  FSM: wri3: sniff -> auth
   dev wri3, got 55 bytes so far
   dev wri3: vlan 31
   FSM: wri3: auth -> config
   FSM: wri3: config -> configured

While this is a port already up twhen the tool starts, in an ssh run:

   FSM: wri17: justup -> sniff
   recvfrom(wri17): 88f7-00267b0003d4
   FSM: wri17: sniff -> auth
   dev wri17, got 185 bytes so far
   dev wri17: vlan 31
   FSM: wri17: auth -> config
   FSM: wri17: config -> configured
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>