circuit_list_path_impl() says 'exit' for internal circs

Related to legacy/trac#1090 (moved):

    tor_asprintf(&cp, "%s%s circ (length %d%s%s):",
                 circ->build_state->is_internal ? "internal" : "exit",
                 circ->build_state->need_uptime ? " (high-uptime)" : "",
                 circ->build_state->desired_path_len,
                 circ->_base.state == CIRCUIT_STATE_OPEN ? "" : ", exit ",
                 circ->_base.state == CIRCUIT_STATE_OPEN ? "" :
                 (nickname?nickname:"*unnamed*"));

That second 'exit' needs to say something else for internal circs. E.g, "last hop".