message: connection.h: Fix comment.
  setConnectionEventCb() does not exist any more, and
  addConnectionCallbacks() seems like the more general replacement.
diff: @@ -227,7 +227,7 @@ class ClientConnection : public virtual Connection {
  public:
  /**
  * Connect to a remote host. Errors or connection events are reported via the event callback
  - * registered via setConnectionEventCb().
  + * registered via addConnectionCallbacks().
  */
  virtual void connect() PURE;
  };
  