Add Zone's virtual associations to Host and VmOrTemplate.

https://bugzilla.redhat.com/show_bug.cgi?id=1121162
Incidentally we also already have a [have_virtual_column matcher](https://github.com/ManageIQ/manageiq/blob/master/vmdb/spec/support/custom_matchers/have_virtual_column.rb), but not one for reflections...perhaps we should make one for reflections.