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/pool_elements_controller_test.rb

@@ -3,8 +3,6 @@ require 'test_helper'
 class PoolElementsControllerTest < ActionDispatch::IntegrationTest
   context "The pools posts controller" do
     setup do
-      mock_pool_archive_service!
-      start_pool_archive_transaction
       @user = travel_to(1.month.ago) {create(:user)}
       @mod = create(:moderator_user)
       as_user do
@@ -13,10 +11,6 @@ class PoolElementsControllerTest < ActionDispatch::IntegrationTest
       end
     end
 
-    teardown do
-      rollback_pool_archive_transaction
-    end
-
     context "create action" do
       should "add a post to a pool" do
         post_auth pool_element_path, @user, params: {:pool_id => @pool.id, :post_id => @post.id, :format => "json"}