"expire superseded" in master

[Nils Goroll]

On 19/12/14 02:14, Jingyi Wei wrote:
> I see that
> bo->ims_obj is set in VBF_Fetch() only if Last-Modified or ETag header
> exists in the previous backend response. Otherwise |ims_obj| is NULL and
> the memory will not be freed, so the actual problem is that there's no
> Last-Modified header in our backend response.

Good point, thank you. LM or ETag are required for issuing a backend conditional
request, but this should be independent of freeing the superseded object. I will
look after this unless someone else does.

Nils