Correctly report PT vs proxy during bootstrap
Previously, or_connection_t did not record whether or not the connection uses a pluggable transport. Instead, it stored the underlying proxy protocol of the pluggable transport in proxy_type. This made bootstrap reporting treat pluggable transport connections as plain proxy connections. Store a separate bit indicating whether a pluggable transport is in use, and decode this during bootstrap reporting. Fixes bug 28925; bugfix on 0.4.0.1-alpha.