So far the finish script exits whenever the service terminated by a
signal (indicated by 256 as first argument). This is the intended
behavior when SIGTERM is being sent: SIGTERM is used on regular shutdown
through the supervisor. We don't want the finish script to shutdown
itself while being taken down by the supervisor already.
However, every other signal which lead to a process exit likely means
trouble: SIGSEGV, SIGILL, etc. In those cases we want the container to
exit. The Supervisor (or restart policy of Docker in the container case)
will take care of restarting if appropriate.
