o Major bugfixes:
    - The PerConnBWRate and Burst config options, along with the
      bwconnrate and bwconnburst consensus params, initialized each conn's
      token bucket values only when the connection is established. Now
      update them if the config options change, and update them every time
      we get a new consensus. Otherwise we can encounter an ugly edge
      case where we initialize an OR conn to client-level bandwidth,
      but then later the relay joins the consensus and we leave it
      throttled. Bugfix on 0.2.2.7-alpha; fixes bug 1830.