Update to latest Bundler pre-release

circle.yml

@@ -10,7 +10,7 @@ machine:
 
 dependencies:
   pre:
-    - gem install bundler -v 1.16.0.pre.1
+    - gem install bundler -v 1.16.0.pre.2
   post:
     - cd helpers/javascript && yarn install
     - cd helpers/php && composer install

lib/bundler_definition_version_patch.rb

@@ -1,39 +1,7 @@
 # frozen_string_literal: true
-require "bundler/vendored_persistent"
-
-# rubocop:disable all
-# TODO: Remove when 1.16.0.pre.2
-module Bundler
-  class PersistentHTTP < Persistent::Net::HTTP::Persistent
-    def warn_old_tls_version_rubygems_connection(uri, connection)
-      return unless connection.use_ssl?
-      return unless (uri.host || "").end_with?("rubygems.org")
-
-      socket = connection.instance_variable_get(:@socket)
-      socket_io = socket&.io
-      return unless socket_io.respond_to?(:ssl_version)
-      ssl_version = socket_io.ssl_version
-
-      case ssl_version
-      when /TLSv([\d\.]+)/
-        version = Gem::Version.new($1)
-        if version < Gem::Version.new("1.2")
-          Bundler.ui.warn \
-            "Warning: Your Ruby version is compiled against a copy of OpenSSL that is very old. " \
-            "Starting in January 2018, RubyGems.org will refuse connection requests from these " \
-            "very old versions of OpenSSL. If you will need to continue installing gems after " \
-            "January 2018, please follow this guide to upgrade: http://ruby.to/tls-outdated.",
-            :wrap => true
-        end
-      end
-    end
-  end
-end
-# rubocop:enable
-
 module BundlerDefinitionVersionPatch
   def index
-    @index ||= super.tap do |index|
+    @index ||= super.tap do
       if ruby_version
         requested_version = ruby_version.to_gem_version_with_patchlevel
         sources.metadata_source.specs <<