Removed deprecated method `columns_for_remove`
Merge pull request #11263 from neerajdotname/columns_for_remove

Removed deprecated method `columns_for_remove`
use American English: "favor" not "favour" [ci skip]

according to http://guides.rubyonrails.org/api_documentation_guidelines.html#english
Correctly handle relations as values in where() for polymorphic associations.