Multiple bug fixes for register_dns

- Bug 1162093 - infrastructure dns improvements
    - https://bugzilla.redhat.com/show_bug.cgi?id=1162093
    - include the dns_infrastructure_key in oo_instrastructure.conf
    - Allow changes to oo_infrastructure.conf file
    - No longer reference fqdn fact in register_dns
- Add comments to templates stating that they are managed by puppet
- Bug 1162901 - ensure correct dns key algo used
    - https://bugzilla.redhat.com/show_bug.cgi?id=1162901
    - Previously register_dns.pp used pick to choose between
      bind_key_algorithm and dns_infrastructure_key_algorithm, but since
      they both had default values of HMAC-MD5,
      dns_infrastructure_key_algorithm was always used.
- Bug 1162454 - default hostnames should use infra zone if provided
    - https://bugzilla.redhat.com/show_bug.cgi?id=1162454
    - If no hostname is provided and dns_infrastructure_zone is configured
      the default hostnames should use dns_infrastructure_zone instead of
      domain variable
- Address issues with variable interpolation within parameters for init.pp   
    - addresses https://github.com/openshift/puppet-openshift_origin/issues/300
- allow recursion to be selectable for dns server