app_vhost still doesn't behave the same as when used from internal recipes

[mikesimons]

Internal recipes iterate node[type]['sites'] where type is either nginx or apache.

Defaults are set on these attrs but are not available to the app_vhost definition separately.

Therefore, given a site definition in node['nginx']['sites] and a site definition from a cookbook using app_vhost directly, app_vhost will fail unless all parameters are provided whereas the attr version will work.

The defaults need refactoring (again) to internalize them in to app_vhost. In order to facilitate introspection of the sites attrs, perhaps we should do this in addition to what is there already.

This means that a little bit of redundant logic will occur when using the built in recipes but that resulting behavior should be consistent.