Set auth_region to $::os_service_default and drop warning

This commit [1] introduced a weird warning that send a warning by
default.

This patch:
* sets auth_region to the default value in OpenStack using
  $::os_service_default
* drops the warning

[1] Id7a6894e5bb12fc7697dfe23e5f9d4a44a719086

Change-Id: Ia5fcbb6333c3466232ac16a552f90f950313230f

manifests/api.pp

@@ -74,7 +74,7 @@
 #   (optional) The region for the authentication service.
 #   If "use_user_token" is not in effect and using keystone auth,
 #   then region name can be specified.
-#   Defaults to 'RegionOne'.
+#   Defaults to $::os_service_default.
 #
 # [*auth_host*]
 #   (optional) DEPRECATED Host running auth service.
@@ -268,7 +268,7 @@ class glance::api(
   $scrub_time               = $::os_service_default,
   $delayed_delete           = $::os_service_default,
   $auth_type                = 'keystone',
-  $auth_region              = 'RegionOne',
+  $auth_region              = $::os_service_default,
   $auth_uri                 = false,
   $identity_uri             = false,
   $pipeline                 = 'keystone',
@@ -343,8 +343,6 @@ class glance::api(
     require => Class['glance']
   }
 
-  warning('Default value for auth_region parameter is different from OpenStack project defaults')
-
   # basic service config
   glance_api_config {
     'DEFAULT/bind_host':               value => $bind_host;

spec/classes/glance_api_spec.rb

@@ -22,7 +22,7 @@ describe 'glance::api' do
       :log_file                 => '/var/log/glance/api.log',
       :log_dir                  => '/var/log/glance',
       :auth_type                => 'keystone',
-      :auth_region              => 'RegionOne',
+      :auth_region              => '<SERVICE DEFAULT>',
       :enabled                  => true,
       :manage_service           => true,
       :backlog                  => '4096',