[PATCH] Log 'set beresp.uncacheable = true' occurrences

[Dridi Boukelmoune]

> Still doesn't say a thing to me. The pass happens in recv (client side) not
> in bereq (backend side).
> Explaining obscure things in the doc is not the right way to go. If anything
> it should complement an already well explained situation.

I meant improving the docs in my patch, like for example the long
description of the VSL record (enumerating the reasons and their
meaning).

> I'd rather move it where it belongs, that is where do_pass is set to 1.

But do_pass is bereq.uncacheable, and until you actually get a
response from the backend I don't think it would make sense to log
that beresp.uncacheable has been set.