Ensure the old nodes are created with the same changeset

Not often important, but the most recent old_node should definitely
have the same changeset as the node itself.

test/factories/node.rb

@@ -16,7 +16,7 @@ FactoryGirl.define do
     trait :with_history do
       after(:create) do |node, _evaluator|
         (1..node.version).each do |n|
-          create(:old_node, :node_id => node.id, :version => n)
+          create(:old_node, :node_id => node.id, :version => n, :changeset => node.changeset)
         end
 
         # For deleted nodes, make sure the most recent old_node is also deleted.