rails/rails — pull request #8588 by marcandre (2012-12-22 17:51:59+00:00)
Title: Fix Migration#reversible by not using `transaction`.

This was causing trouble in mysql/mysql2 because transactions
are not supported when modifying schema. [#8267]

@carlosantoniodasilva There are other failures to fix, but my PB is running out of juice, so I'll handle those later today.