Bug#407171: proxy stops working after upgrading from sarge

[Peter Samuelson <peter@p12n.org>]

# this is a sarge upgrade issue that I think should be RC
severity 407171 serious
thanks

[Per Olofsson]
> I upgraded from sarge and Apache's proxy stopped working. The reason
> was that mod_proxy_http wasn't loaded, but this was in no way obvious
> since that module was not required in sarge.

Well, the module was required, but a2enmod added it automatically,
along with mod_disk_cache.  Now it no longer does.

I think I've fixed this for the next upload (to be done in the next day
or two - I'm away from home but I'll still try), and I consider it a
release-critical upgrade issue, so I hope the release managers will
allow it into etch.

Sorry for not responding earlier,
Peter