Still touch associations when theres no timestamp

Prior to Rails 4.0.4 when touching a object which doesn't have timestamp
attributes (updated_at / updated_on) rails would still touch all
associations. After 73ba2c14cd it updates
associations but rollsback because `touch` would return nil since
there's no timestamp attribute

activerecord/lib/active_record/persistence.rb

@@ -452,6 +452,8 @@ module ActiveRecord
         changed_attributes.except!(*changes.keys)
         primary_key = self.class.primary_key
         self.class.unscoped.where(primary_key => self[primary_key]).update_all(changes) == 1
+      else
+        true
       end
     end
 

activerecord/test/cases/associations/belongs_to_associations_test.rb

@@ -340,6 +340,17 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_queries(1) { line_item.touch }
   end
 
+  def test_belongs_to_with_touch_option_on_touch_without_updated_at_attributes
+    assert !LineItem.column_names.include?("updated_at")
+
+    line_item = LineItem.create!
+    invoice = Invoice.create!(line_items: [line_item])
+    initial = invoice.updated_at
+    line_item.touch
+
+    refute_equal initial, invoice.reload.updated_at
+  end
+
   def test_belongs_to_with_touch_option_on_touch_and_removed_parent
     line_item = LineItem.create!
     Invoice.create!(line_items: [line_item])