Change older Paperclip database migrations for consistency (#30204)

db/migrate/20170330164118_add_attachment_data_to_imports.rb

@@ -3,7 +3,11 @@
 class AddAttachmentDataToImports < ActiveRecord::Migration[4.2]
   def self.up
     change_table :imports do |t|
-      t.attachment :data
+      # The following corresponds to `t.attachment :data` in an older version of Paperclip
+      t.string :data_file_name
+      t.string :data_content_type
+      t.integer :data_file_size
+      t.datetime :data_updated_at
     end
   end