rails/rails — pull request #16531 by cwjenkins (2014-08-17 18:25:43+00:00)
Title: Support unscoping default_scope in eager_loaded associations

For eager_loaded joins move the default scope to the front of the scope chain to be merged first.
For preloading check values for unscope and add to the scope being built unscope_values.
On preload, no need to change merge sequence given default scope is merged first.