This is pretty hacky but it is a custom implementation of Gem::ConfigFile so that we don't load any gemrc files.
# File lib/vagrant/bundler.rb, line 269 def initialize # We _can not_ `super` here because that can really mess up # some other configuration state. We need to just set everything # directly. @api_keys = {} @args = [] @backtrace = false @bulk_threshold = 1000 @hash = {} @update_sources = true @verbose = true end