Downgrade needs to call correct method.

_is_owner, not is_owner.

lib/Lacuna/RPC/Building.pm

@@ -261,7 +261,7 @@ sub downgrade {
         unless ($body->parliament && $body->parliament->effective_level >= 2) {
             confess [1013, 'You need to have a level 2 Parliament to downgrade a module.'];
         }
-        unless ($self->is_owner($session, $building)) {
+        unless ($self->_is_owner($session, $building)) {
             my $name = $building->name.' ('.$building->x.','.$building->y.')';
             my $proposition = Lacuna->db->resultset('Lacuna::DB::Result::Propositions')->new({
                 type            => 'DowngradeModule',

var/www/public/changes.txt

@@ -2,6 +2,7 @@
  - Add: Adding docker support.
  - Fix: Emails to GG owners during fissure explosion were missing numbers.
  - Fix: Halls don't need to show up as buildable.
+ - Fix: Downgrade of SS modules fixed.
 
 3.0918:
  - Fix: Unallied players should never see anyone else in purple on the starmap.