Fix environment gems_path location

lib/vagrant/environment.rb

@@ -121,7 +121,7 @@ module Vagrant
       @home_path  = Util::Platform.fs_real_path(@home_path)
       @boxes_path = @home_path.join("boxes")
       @data_dir   = @home_path.join("data")
-      @gems_path  = @home_path.join("gems")
+      @gems_path  = Vagrant::Bundler.instance.plugin_gem_path
       @tmp_path   = @home_path.join("tmp")
       @machine_index_dir = @data_dir.join("machine-index")
 

test/unit/vagrant/environment_test.rb

@@ -67,6 +67,13 @@ describe Vagrant::Environment do
     end
   end
 
+  describe "#gems_path" do
+    it "is set to Vagrant::Bundler defined path" do
+      instance = described_class.new
+      expect(instance.gems_path).to eq(Vagrant::Bundler.instance.plugin_gem_path)
+    end
+  end
+
   describe "#home_path" do
     it "is set to the home path given" do
       Dir.mktmpdir("vagrant-test-env-home-path-given") do |dir|