Properly deprecate setup_mail

lib/devise/mailers/helpers.rb

@@ -10,6 +10,11 @@ module Devise
 
       protected
 
+      def setup_mail(*args)
+        ActiveSupport::Deprecation.warn "setup_mail is deprecated, please use devise_mail instead", caller
+        devise_mail(*args)
+      end
+
       # Configure default email options
       def devise_mail(record, action)
         initialize_from_record(record)