Fix slow fallback of CopyAccountStats migration setting stats to 0 (mastodon#9930)

Author: Gargron

db/migrate/20181116173541_copy_account_stats.rb

@@ -44,7 +44,7 @@ def up_slow
     # uniqueness violations that we need to skip over
     Account.unscoped.select('id, statuses_count, following_count, followers_count, created_at, updated_at').find_each do |account|
       begin
-        params = [[nil, account.id], [nil, account.statuses_count], [nil, account.following_count], [nil, account.followers_count], [nil, account.created_at], [nil, account.updated_at]]
+        params = [[nil, account.id], [nil, account[:statuses_count]], [nil, account[:following_count]], [nil, account[:followers_count]], [nil, account.created_at], [nil, account.updated_at]]
         exec_insert('INSERT INTO account_stats (account_id, statuses_count, following_count, followers_count, created_at, updated_at) VALUES ($1, $2, $3, $4, $5, $6)', nil, params)
       rescue ActiveRecord::RecordNotUnique
         next