set execute bit on test_file

b/c it is intended to be executed.

spec/classes/openstack_test_file_spec.rb

@@ -0,0 +1,7 @@
+require 'spec_helper'
+
+describe 'openstack::test_file' do
+  it do
+    should contain_file('/tmp/test_nova.sh').with_mode('0751')
+  end
+end