This converts fsm.c to use the new diagnostics. We keep printing
the timestamp for fsm messages, which means diag.c::__pp_diag is
somehow duplicated here (in what was called pp_timed_printf).

This is the output with "-d 1" (or "-d "100") on a forced-slave ("-g"):

  diag level: 10000000
  diag-fsm-1-eth0: 1362666577.043: ENTER initializing, packet len 0
  diag-fsm-1-eth0: 1362666577.045: LEAVE initializing (next:   4 in 0 ms)
  diag-fsm-1-eth0: 1362666577.045: ENTER listening, packet len 0
  diag-fsm-1-eth0: 1362666577.045: listening: reenter in 11999 ms
  diag-fsm-1-eth0: 1362666587.204: listening: reenter in 1840 ms
  diag-fsm-1-eth0: 1362666588.388: LEAVE listening (next:   9 in 0 ms)
  diag-fsm-1-eth0: 1362666588.388: ENTER slave, packet len 44
  diag-fsm-1-eth0: 1362666588.389: slave: reenter in 889 ms
  diag-fsm-1-eth0: 1362666589.219: slave: reenter in 59 ms
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>