This reverts commit de3e581e.

tests/saintmode/test04.vtc from varnish-modules revealed that there may
be use cases where it is implied that vcl_backend_error will leave a
ttl=0 object and the sale object will remain in place.

This can be resolved by:

	- return(abandon) for these cases or
	- making the HSH_Kill conditional on bo->fetch_objcore->ttl > 0

but I already has concerns regarding the impact of this change and have
them even more now.

We need time to ponder about the consequences and a documented
inefficiency is better than unexpected behaviour in a release.