Comment 6 for bug 1506242

@Melanie, @Mark,

Simplest fix would be to raise BuildAbortException with the original spawn failure, and simply log "Could not clean up failed build" line. Please see the code snippet [1]

Three reasons for doing this:

1. The only reason why the call landed there was because spawn failed. So knowing that error is more important than anything else
2. IMHO, "Could not clean up failed build" does not give any useful information about any failure. Its probably OK to log it, but not very useful to have that as instance fault.
3. Combining all of the statements is not possible because of the character limit of "message" field

[1]
        try:
            yield resources
        except Exception as exc:
            with excutils.save_and_reraise_exception() as ctxt:
                if not isinstance(exc, (exception.InstanceNotFound,
                    exception.UnexpectedDeletingTaskStateError)):
                        LOG.exception(_LE('Instance failed to spawn'),
                                instance=instance)
                # Make sure the async call finishes
                if network_info is not None:
                    network_info.wait(do_raise=False)
                # if network_info is empty we're likely here because of
                # network allocation failure. Since nothing can be reused on
                # rescheduling it's better to deallocate network to eliminate
                # the chance of orphaned ports in neutron
                deallocate_networks = False if network_info else True
                try:
                    self._shutdown_instance(context, instance,
                            block_device_mapping, requested_networks,
                            try_deallocate_networks=deallocate_networks)
                except Exception:
                    ctxt.reraise = False
                    LOG.exception(_LE('Could not clean up failed build,' <<<<
                                                          ' not rescheduling'), <<<
                                                          instance=instance) <<<
                    raise exception.BuildAbortException(
                            instance_uuid=instance.uuid, reason=exc) <<<