Grab the subscription name from Config#central_subscription_name

Command executed:

        $ git grep -l central_commands_subscription | xargs sed -ie 's/central_commands_subscription/central_subscription_name/g'

lib/tasks/central_updates_subscriber.rake

@@ -12,7 +12,7 @@ namespace :message_broker do
       logger = Carto::Common::Logger.new($stdout)
 
       message_broker = Carto::Common::MessageBroker.new(logger: logger)
-      subscription_name = Carto::Common::MessageBroker::Config.instance.central_commands_subscription
+      subscription_name = Carto::Common::MessageBroker::Config.instance.central_subscription_name
       subscription = message_broker.get_subscription(subscription_name)
       notifications_topic = message_broker.get_topic(:cartodb_central)
       central_user_commands = Carto::Subscribers::CentralUserCommands.new(