Add note about removing patch fix and add test

lib/vagrant/bundler.rb

@@ -12,8 +12,6 @@ require "rubygems/name_tuple"
 require_relative "shared_helpers"
 require_relative "version"
 require_relative "util/safe_env"
-require_relative "util/platform"
-require "vagrant/util/subprocess"
 
 module Vagrant
   # This class manages Vagrant's interaction with Bundler. Vagrant uses
@@ -43,6 +41,9 @@ module Vagrant
       @plugin_gem_path = Vagrant.user_data_path.join("gems", RUBY_VERSION).freeze
       @logger = Log4r::Logger.new("vagrant::bundler")
 
+      # TODO: Remove fix when https://github.com/rubygems/rubygems/pull/2735
+      # gets merged and released
+      #
       # Because of a rubygems bug, we need to set the gemrc file path
       # through this method rather than relying on the environment varible
       # GEMRC. On windows, that path gets split on `:`: and `;`, which means

test/unit/vagrant/bundler_test.rb

@@ -28,6 +28,19 @@ describe Vagrant::Bundler do
     expect(subject.env_plugin_gem_path).to be_nil
   end
 
+  describe "#initialize" do
+    let(:gemrc_location) { "C:\\My\\Config\\File" }
+
+    it "should set up GEMRC through a flag instead of GEMRC" do
+      allow(ENV).to receive(:[]).with("VAGRANT_HOME")
+      allow(ENV).to receive(:[]).with("USERPROFILE")
+
+      allow(ENV).to receive(:[]).with("GEMRC").and_return(gemrc_location)
+      expect(Gem::ConfigFile).to receive(:new).with(["--config-file", gemrc_location])
+      init_subject = described_class.new
+    end
+  end
+
   describe "#deinit" do
     it "should provide method for backwards compatibility" do
       subject.deinit