FEATURE: remove the timecop gem

We should only have one way of mocking time, misuse of timecop
was causing build stability issues

spec/services/topic_timestamp_changer_spec.rb

@@ -21,26 +21,25 @@ describe TopicTimestampChanger do
       let(:new_timestamp) { old_timestamp - 2.day }
 
       it 'changes the timestamp of the topic and opening post' do
-        Timecop.freeze do
-          TopicTimestampChanger.new(topic: topic, timestamp: new_timestamp.to_f).change!
+        freeze_time
+        TopicTimestampChanger.new(topic: topic, timestamp: new_timestamp.to_f).change!
 
-          topic.reload
-          [:created_at, :updated_at, :bumped_at].each do |column|
-            expect(topic.public_send(column)).to be_within(1.second).of(new_timestamp)
-          end
-
-          p1.reload
-          [:created_at, :updated_at].each do |column|
-            expect(p1.public_send(column)).to be_within(1.second).of(new_timestamp)
-          end
-
-          p2.reload
-          [:created_at, :updated_at].each do |column|
-            expect(p2.public_send(column)).to be_within(1.second).of(new_timestamp + 1.day)
-          end
-
-          expect(topic.last_posted_at).to be_within(1.second).of(p2.reload.created_at)
+        topic.reload
+        [:created_at, :updated_at, :bumped_at].each do |column|
+          expect(topic.public_send(column)).to be_within(1.second).of(new_timestamp)
         end
+
+        p1.reload
+        [:created_at, :updated_at].each do |column|
+          expect(p1.public_send(column)).to be_within(1.second).of(new_timestamp)
+        end
+
+        p2.reload
+        [:created_at, :updated_at].each do |column|
+          expect(p2.public_send(column)).to be_within(1.second).of(new_timestamp + 1.day)
+        end
+
+        expect(topic.last_posted_at).to be_within(1.second).of(p2.reload.created_at)
       end
 
       describe 'when posts have timestamps in the future' do
@@ -48,15 +47,16 @@ describe TopicTimestampChanger do
         let(:p3) { Fabricate(:post, topic: topic, created_at: new_timestamp + 3.day) }
 
         it 'should set the new timestamp as the default timestamp' do
-          Timecop.freeze do
-            p3
-            TopicTimestampChanger.new(topic: topic, timestamp: new_timestamp.to_f).change!
+          freeze_time
 
-            p3.reload
+          p3
 
-            [:created_at, :updated_at].each do |column|
-              expect(p3.public_send(column)).to be_within(1.second).of(new_timestamp)
-            end
+          TopicTimestampChanger.new(topic: topic, timestamp: new_timestamp.to_f).change!
+
+          p3.reload
+
+          [:created_at, :updated_at].each do |column|
+            expect(p3.public_send(column)).to be_within(1.second).of(new_timestamp)
           end
         end
       end