POC showing keystone running on Apache with mod_wsgi

Running python apps via shitty python web servers is painful. Running them behind
apache + mod_wsgi is much more interesting and provides some good apache style logs
for troubleshooting.

Since horizon is already using apache it was relatively simple to break the apache parts
out into their own role so that both horizon and keystone can utilize it.

I would love to look at using this for all of the openstack APIs and even look at using
mod_loadbalancer to replace haproxy,  I think this would be an excellent way to reduce the
complexity of our stack and provide something that the majority of devops^H^H^H^H^H^Hsystem
admins know how to use/troubleshoot in the form of apache.
Why does this directory need to be writable by the keystone user?