Fix zone-level always-dry-run functionality

Thanks @offmindby!

octodns/manager.py

@@ -273,12 +273,18 @@ class Manager(object):
             for target, plan in plans:
                 plan.raise_if_unsafe()
 
-        if dry_run or config.get('always-dry-run', False):
+        if dry_run:
             return 0
 
         total_changes = 0
         self.log.debug('sync:   applying')
+        zones = self.config['zones']
         for target, plan in plans:
+            zone_name = plan.existing.name
+            if zones[zone_name].get('always-dry-run', False):
+                self.log.info('sync: zone=%s skipping always-dry-run',
+                              zone_name)
+                continue
             total_changes += target.apply(plan)
 
         self.log.info('sync:   %d total changes', total_changes)

tests/test_octodns_manager.py

@@ -88,6 +88,14 @@ class TestManager(TestCase):
                 .sync(['not.targetable.'])
         self.assertTrue('does not support targeting' in ctx.exception.message)
 
+    def test_always_dry_run(self):
+        with TemporaryDirectory() as tmpdir:
+            environ['YAML_TMP_DIR'] = tmpdir.dirname
+            tc = Manager(get_config_filename('always-dry-run.yaml')) \
+                .sync(dry_run=False)
+            # only the stuff from subzone, unit.tests. is always-dry-run
+            self.assertEquals(3, tc)
+
     def test_simple(self):
         with TemporaryDirectory() as tmpdir:
             environ['YAML_TMP_DIR'] = tmpdir.dirname