Update destroy action to use the new destroy syntax for VM

lib/vagrant/actions/vm/destroy.rb

@@ -11,7 +11,7 @@ module Vagrant
 
         def destroy_vm
           logger.info "Destroying VM and associated drives..."
-          @runner.vm.destroy(:destroy_image => true)
+          @runner.vm.destroy(:destroy_medium => :delete)
         end
 
         def depersist

test/vagrant/actions/vm/destroy_test.rb

@@ -22,7 +22,7 @@ class DestroyActionTest < Test::Unit::TestCase
 
   context "destroying the VM" do
     should "destroy VM and attached images" do
-      @vm.expects(:destroy).with(:destroy_image => true).once
+      @vm.expects(:destroy).with(:destroy_medium => :delete).once
       @action.destroy_vm
     end
   end