title: Unsupported config option for services service: 'httpd'
body: <p>I am getting this on Ubuntu with a fresh install of Docker 1.12.0</p>
  
  <p>It works on all other colleagues installations with the same version of Docker.</p>
  
  <p>This is the docker-compose.yml</p>
  
  <pre><code>version: '2'
  
  networks:
    backend:
  
  services:
    httpd:
      image: httpd:2.4
      depends_on:
        - tomcat
      networks:
        - backend
      ports:
        - "80:80"
      volumes:
        - ./httpd/httpd.conf:/usr/local/apache2/conf/httpd.conf
  
    tomcat:
      image: tomcat:8.0-jre8-alpine
      depends_on:
        - mongodb
      networks:
        - backend
      ports:
        - "8080:8080"
      volumes:
        - ./tomcat/webapps:/usr/local/tomcat/webapps/
      environment:
        - ITONICS_CONFIG=docker
        - CATALINA_OPTS=-Xms512M -Xmx2048M
  
    mongodb:
      image: mongo:3.2
      volumes:
        - ./mongo/db:/data/db
      networks:
        - backend
      ports:
        - "27017:27017"
  </code></pre>