[MERGE][bug #230223] Make both http implementations raise appropriate exceptions on 403 Forbidden

[Andrew Bennetts]

Vincent Ladeuil wrote:
> >>>>> "Andrew" == Andrew Bennetts <andrew at canonical.com> writes:
[...]
>     Andrew> That explanation makes sense to me.
> 
> Good. I settled with a simple patch then, I mentioned some
> refactoring on IRC, but it turned out it will have been renaming
> _post into _send_smart_request and that seemed gratuitous at that
> time.
[...]
> 
> I'll merge that.

The final version looks good to me.  Thanks for fixing this!

-Andrew.