Add missing boilerplate.

test/integration/targets/include_import/playbook/sub_playbook/library/helloworld.py

@@ -14,6 +14,9 @@
 # You should have received a copy of the GNU General Public License
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
 from ansible.module_utils.basic import AnsibleModule