Code review comment for lp:~andreserl/maas/packaging_lp1236544

In configure_cluster_http(), it might be worth extracting the new code into a separate function, e.g. enable_apache_version_module(). That way its purpose is immediately obvious, and when we maintain configure_cluster_http() in the future, we won't have to worry about exactly where else in the function COMMON_STATE might be used.