bind9: Prepare to enable pool management by default

This change is follow-up of 22019e46e2553e047fd7706c82d29d3cfb978e39
and prepares to enable setup of pool by default.

Change-Id: Ic457eaf01d613ad5850a2b4d020f7d82371b94fe

manifests/backend/bind9.pp

@@ -72,7 +72,7 @@ class designate::backend::bind9 (
   $mdns_hosts       = ['127.0.0.1'],
   $mdns_port        = 5354,
   $configure_bind   = true,
-  $manage_pool      = false,
+  $manage_pool      = undef,
   # DEPRECATED PARAMETERS
   $rndc_host        = undef,
 ) {
@@ -128,7 +128,13 @@ class designate::backend::bind9 (
     'backend:bind9/rndc_key_file'    : ensure => absent;
   }
 
-  if $manage_pool {
+  # TODO(tkajinam): Update default after Yoga release.
+  if $manage_pool == undef {
+    warning('Pool management will be enabled by default in a future release, \
+Make sure manage_pool is set to disable the feature')
+  }
+
+  if pick($manage_pool, false) {
     file { '/etc/designate/pools.yaml':
       ensure  => present,
       path    => '/etc/designate/pools.yaml',

releasenotes/notes/bind9-prepare-enable-pool-management-bebd5b552eda6293.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Default value of the ``designate::backend::bind9::manage_pool`` parameter
+    will be changed from ``false`` to ``true`` in a future release. Make sure
+    the parameter is set to disabled management of pools.