[bundler/bundler] Adapt to the way my automatiek patch works

https://github.com/bundler/bundler/commit/b8ee4aec0b

lib/bundler/vendor/net-http-persistent/lib/net/http/persistent.rb

@@ -1,7 +1,7 @@
 require 'net/http'
 require 'uri'
 require 'cgi' # for escaping
-require_relative '../../../../connection_pool/lib/connection_pool'
+require 'bundler/vendor/connection_pool/lib/connection_pool'
 
 begin
   require 'net/http/pipeline'