Merge pull request #4099 from mitchellh/fix-issue-2476-chef-client-node-cleanup

provisioners/chef: clean bundle env when executing chef client

plugins/provisioners/chef/provisioner/chef_client.rb

@@ -104,6 +104,9 @@ module VagrantPlugins
             "vagrant.provisioners.chef.deleting_from_server",
             deletable: deletable, name: node_name))
 
+          # Knife is not part of the current Vagrant bundle, so it needs to run
+          # in the context of the system.
+          Bundler.with_clean_env do
             command = ["knife", deletable, "delete", "--yes", node_name]
             r = Vagrant::Util::Subprocess.execute(*command)
             if r.exit_code != 0
@@ -117,4 +120,5 @@ module VagrantPlugins
         end
       end
     end
+  end
 end