Puppet install zuul on Ubuntu 14.04 Trusty fails because Apache/2.4.7
does not have mod_mem_cache. According to [1], we should use
mod_cache_disk instead.
"These modules have been removed: mod_authn_default, mod_authz_default,
mod_mem_cache. If you were using mod_mem_cache in 2.2,
look at mod_cache_disk in 2.4."
Add configuration to cache /status.json using mod_cache_disk.
Allow access to the 'DocumentRoot' path, which is disallowed on 14.04
by default.
[1] http://httpd.apache.org/docs/trunk/upgrading.html
Change-Id: I734b5c45e1e088364328e9fc5ec5932d3bfe32c5
be4aff60dc