bgpd: Make the exponential backoff on BGP stop_with_error slower

* bgp_fsm.c: (bgp_stop_with_error) peer->v_start * 2^x exponential back
  off, up to max of 120s, ramps up fast. Use a slower back off, implemented
  via a helper.
  (back_off_exp2) The original 2^x back off.
  (back_off_exp2_bias) Exp back-off, but biased down by the initial value to
  slow the rampup initially.
1 file changed