tests: fix post and pool version tests helpers.

* Fix the pool version SQS service to always be mocked before every
  test. Before we had to manually set it up before every test dealing
  with pool versions.

* Fix it so that we reconnect to the post/pool version databases before
  every test. Before using $ARCHIVE_DATABASE_URL to set the database url
  failed because environment variables weren't loaded by dotenv yet when
  connections were first established.

test/functional/pools_controller_test.rb

@@ -3,10 +3,6 @@ require 'test_helper'
 class PoolsControllerTest < ActionDispatch::IntegrationTest
   context "The pools controller" do
     setup do
-      mock_pool_archive_service!
-      PoolVersion.sqs_service.stubs(:merge?).returns(false)
-      start_pool_archive_transaction
-
       travel_to(1.month.ago) do
         @user = create(:user)
         @mod = create(:moderator_user)
@@ -17,10 +13,6 @@ class PoolsControllerTest < ActionDispatch::IntegrationTest
       end
     end
 
-    teardown do
-      rollback_pool_archive_transaction
-    end
-
     context "index action" do
       should "list all pools" do
         get pools_path