Remove deprecated warn option from docker-hubot example.

Author: geerlingguy

docker-hubot/main.yml

@@ -37,8 +37,6 @@
         apt-get remove --purge -y python &&
         rm -rf /var/lib/apt/lists/*
       delegate_to: '{{ container_name }}'
-      args:
-        warn: false
 
     - name: Commit the container.
       command: >