records not archiving on Rails 3.1.3

[xxx]

Hi,

I'm seeing this issue both in our app as well as in the acts_as_archive test suite after porting it to work with Rails 3.1. The delete_sql alias is never being called as far as I can tell. I don't know if Rails is using a new codepath or something else is afoot. The method is being included correctly into the adapter, but is not being called when a record is destroyed, so nothing is archived.

[xxx]

I've done some work and got this working on 3.1, at the cost of backward compatability, so I won't send a pull request, but the commit is here.