This also covers _dbus_server_new_for_socket(), which is one of the
worse places in terms of complexity of the error-unwinding path
(3 labels).
Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Philip Withnall <withnall@endlessm.com>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=89104