FIX: Topic timers being incorrectly trashed!.

https://meta.discourse.org/t/temporary-timed-closure-of-topic-not-re-opening-topic/67877

spec/controllers/topics_controller_spec.rb

@@ -420,6 +420,7 @@ describe TopicsController do
 
         expect(response).to be_success
         expect(@topic.reload.closed).to eq(false)
+        expect(@topic.topic_timers).to eq([])
 
         body = JSON.parse(response.body)