Broken find last when no order is given.

When finding the last item through an association or a named_scope in an association I get the error:

User.first.logs.find_last_by_type('foo')
NoMethodError: private method `split' called for nil:NilClass
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:1540:in `reverse_sql_order'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:1529:in `find_last'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:614:in `find'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:1907:in `find_last_by_credits'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:1892:in `send'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:1892:in `method_missing'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/associations/association_collection.rb:374:in `send'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/associations/association_collection.rb:374:in `method_missing'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/base.rb:2148:in `with_scope'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/associations/association_proxy.rb:206:in `send'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/associations/association_proxy.rb:206:in `with_scope'
	from ./../frontend/vendor/rails/activerecord/lib/active_record/associations/association_collection.rb:370:in `method_missing'
	from (irb):5

I tracked it down to scoped? returning true because the :order key was set by the association, but was nil. Attached is a patch that fixes that by checking if the key is there and is not nil