Merge branch 'maint-0.2.8' into maint-0.2.9

  o Minor bugfixes (network layer):

    - When closing a connection via close_connection_immediately(), we

      mark it as "not blocked on bandwidth", to prevent later calls

      from trying to unblock it, and give it permission to read. This

      fixes a backtrace warning that can happen on relays under various

      circumstances. Fixes bug 24167; bugfix on 0.1.0.1-rc.

  connection_unregister_events(conn);

  /* Prevent the event from getting unblocked. */

  conn->read_blocked_on_bw =

    conn->write_blocked_on_bw = 0;

  if (SOCKET_OK(conn->s))

    tor_close_socket(conn->s);

  conn->s = TOR_INVALID_SOCKET;