Add missing require "fileutils"

Author: larskanis

spec/helpers.rb

@@ -5,6 +5,7 @@
 require 'shellwords'
 require 'pg'
 require 'openssl'
+require 'fileutils'
 require 'objspace'
 require_relative 'helpers/scheduler.rb'
 require_relative 'helpers/tcp_gate_scheduler.rb'