Right now the first stages of the "first" OR_CONN get reported as `BOOTSTRAP_STATUS_CONN_DIR` and `BOOTSTRAP_STATUS_HANDSHAKE` (the latter is a special bootstrap phase that gets translated into `BOOTSTRAP_STATUS_HANDSHAKE_DIR` or `BOOTSTRAP_STATUS_HANDSHAKE_OR` depending on how much progress was previously reported. The logic in functions that report these events should be moved up to a new abstraction so lower level code has to track less high-level state. This also eliminates some logic in `control_event_bootstrap()` that tries to figure out whether a given handshake attempt corresponds to a directory connection or an application circuit connection.