FEATURE: remove the timecop gem

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

plugins/poll/lib/tasks/migrate_old_polls.rake

@@ -25,7 +25,6 @@ end
 
 desc "Migrate old polls to new syntax"
 task "poll:migrate_old_polls" => :environment do
-  require "timecop"
   # iterate over all polls
   PluginStoreRow.where(plugin_name: "poll")
                 .where("key LIKE 'poll_options_%'")
@@ -39,7 +38,7 @@ task "poll:migrate_old_polls" => :environment do
       # skip if already migrated
       next if post.custom_fields.include?("polls")
       # go back in time
-      Timecop.freeze(post.created_at + 1.minute) do
+      freeze_time(post.created_at + 1.minute) do
         raw = post.raw.gsub(/\n\n([ ]*[-\*\+] )/, "\n\\1") + "\n\n"
         # fix the RAW when needed
         if raw !~ /\[poll\]/

plugins/poll/spec/controllers/posts_controller_spec.rb

@@ -92,7 +92,7 @@ describe PostsController do
       describe "within the first 5 minutes" do
 
         let(:post_id) do
-          Timecop.freeze(4.minutes.ago) do
+          freeze_time(4.minutes.ago) do
             xhr :post, :create, { title: title, raw: "[poll]\n- A\n- B\n[/poll]" }
             ::JSON.parse(response.body)["id"]
           end
@@ -122,7 +122,7 @@ describe PostsController do
         let(:updated) { "before\n\n[poll]\n- A\n- B\n[/poll]\n\nafter" }
 
         let(:post_id) do
-          Timecop.freeze(6.minutes.ago) do
+          freeze_time(6.minutes.ago) do
             xhr :post, :create, { title: title, raw: poll }
             ::JSON.parse(response.body)["id"]
           end