Remove unnecessary extra variable

[rowanthorpe]

trafficstars

A variable host_all_addresses already exists (created in tasks/zones.yaml) for "the union of Ansible IPv4 and IPv6 addresses", but in templates/etc_named.conf.j2 a temporary variable _all_addresses is created and used for the exact same purpose. This just removes the creation of the extra variable and changes the two places it's referenced to use the existing variable.

[bertvv]

Thanks for catching this! The code is becoming so complex that it's easy to miss these mistakes...