title: docker-compose not recognizing env_file file/location, and still tries to use the default .env
body: <p>Here's my compose file <code>dev.yml</code></p>
  
  <pre><code>version: '2'
  
  volumes:
    rethinkdb_data_dev: {}
  
  services:
    rethinkdb:
      image: rethinkdb:latest
      volumes:
        - rethinkdb_data_dev:/home/rethinkdb_data
  
    rabbitmq:
      image: rabbitmq:latest
  
    fumio:
      build:
        context: .
        dockerfile: ./compose/fumio_dev/Dockerfile
      depends_on:
        - rethinkdb
        - rabbitmq
      links:
        - rethinkdb
        - rabbitmq
      env_file: ./compose/fumio_dev/dev.env
      environment:
        - GIRLFRIEND_FUMIO_CONFIG=development
        - GIRLFRIEND_FUMIO_NOSQLDATABASE_HOST=rethinkdb
      ports:
        - "${GIRLFRIEND_FUMIO_PORT}:8001"
  </code></pre>
  
  <p>The <code>environment</code> inside the <code>dev.yml</code> file is intentional, so I can override them inside with <code>dev.env</code> if needed.</p>
  
  <p>My <code>dev.env</code> file, located inside <code>compose/fumio_dev/</code> folder, relative to the <code>dev.yml</code> file.</p>
  
  <pre><code>GIRLFRIEND_FUMIO_PORT=8000
  </code></pre>
  
  <p>Here's what happens when I run <code>docker-compose -f dev.yml build</code></p>
  
  <p><a href="https://i.stack.imgur.com/FY2l1.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FY2l1.png" alt="enter image description here"></a></p>
  
  <p>If I provide <code>.env</code> file in the root folder, it runs fine, docker-compose ignores the <code>env_file</code>'s value and try to use the default <code>.env</code> instead. So docker-compose env_file is somehow not working as intended or I'm missing something?</p>
  
  <p>My docker-compose version is 1.8.0, I downgraded it to 1.7.1 but still no luck (installed using pip).</p>