Apache configuration not working with 2.4 ("Forbidden")

The Apache configuration shipped with devstack isn't compatible with Apache 2.4, and therefore doesn't work by default on Fedora 18.

Changing a couple of lines in horizon.conf resolved this:

    <Directory /opt/stack/horizon/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Order allow,deny
        allow from all
    </Directory>

to

    <Directory /opt/stack/horizon/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Require all granted
    </Directory>

(From http://httpd.apache.org/docs/trunk/upgrading.html)