Merge ~bjornt/maas:bug-1908087-2.9 into maas:2.9

[Björn Tillenius]

LP #1908087 - Reverse DNS for non-maas RFC1918 zones fails inside maas

Considering MAAS is usually configured to point to another DNS within a
DC, having empty-zones-enable set to 'no' makes the most sense.
Especially since that was the behaviour in bind9 before MAAS 2.9.

In the future we might want to make this optional.

(cherry picked from commit 39e32f00c7b02ac792f390ee1f8fb1298afc9aa5)

[Björn Tillenius (bjornt)]

Self-approve backport.

review: Approve

diff --git a/src/provisioningserver/dns/tests/test_actions.py b/src/provisioningserver/dns/tests/test_actions.py
index 3aae795..72c5b5a 100644
--- a/src/provisioningserver/dns/tests/test_actions.py
+++ b/src/provisioningserver/dns/tests/test_actions.py
@@ -258,7 +258,7 @@ class TestConfiguration(MAASTestCase):
         };
 
         dnssec-validation %s;
-
+        empty-zones-enable no;
         allow-query { any; };
         allow-recursion { trusted; };
         allow-query-cache { trusted; };
@@ -267,7 +267,6 @@ class TestConfiguration(MAASTestCase):
         expected_options_content %= tuple(upstream_dns) + (
             expected_dnssec_validation,
         )
-
         self.assertThat(
             expected_options_file, FileContains(expected_options_content)
         )
diff --git a/src/provisioningserver/templates/dns/named.conf.options.inside.maas.template b/src/provisioningserver/templates/dns/named.conf.options.inside.maas.template
index ba1aee3..d76fcfa 100644
--- a/src/provisioningserver/templates/dns/named.conf.options.inside.maas.template
+++ b/src/provisioningserver/templates/dns/named.conf.options.inside.maas.template
@@ -7,7 +7,7 @@ forwarders {
 {{endif}}
 
 dnssec-validation {{dnssec_validation}};
-
+empty-zones-enable no;
 
 {{if not upstream_allow_query}}
 allow-query { any; };