rails/rails — pull request #7723 by steveklabnik (2012-09-21 12:09:06+00:00)
Title: Backport #3544 to 3-2-stable

Rename field_changed? to _field_changed? so that users can create a field named field
Conflicts:

activerecord/lib/active_record/core.rb
activerecord/test/cases/dirty_test.rb