o Minor bugfixes (circuit, hidden service)
    - When closing a circuit, the reason for doing so was assigned from an int
      value to a uint16_t which is quite a problem for negative values that are
      our internal reasons (ex: END_CIRC_REASON_IP_NOW_REDUNDANT). On the HS
      side, this was causing introduction points to be flagged as unusable
      because the reason wasn't the right one due to the bad conversion.
      Partially fixes bug 21056 and fixes bug 20307; Bugfix on 0.2.8.1-alpha.