Docker Compose inside Vagrant VM is broken

[geerlingguy]

Basically, run sudo pip install docker-compose, then:

# docker-compose up -d
WARNING: Dependency conflict: an older version of the 'docker-py' package may be polluting the namespace. If you're experiencing crashes, run the following command to remedy the issue:
pip uninstall docker-py; pip uninstall docker; pip install docker
Pulling memcached (memcached:alpine)...
Traceback (most recent call last):
  File "/bin/docker-compose", line 11, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/site-packages/compose/cli/main.py", line 68, in main
    command()
  File "/usr/lib/python2.7/site-packages/compose/cli/main.py", line 121, in perform_command
    handler(command, command_options)
  File "/usr/lib/python2.7/site-packages/compose/cli/main.py", line 938, in up
    scale_override=parse_scale_args(options['--scale']),
  File "/usr/lib/python2.7/site-packages/compose/project.py", line 430, in up
    svc.ensure_image_exists(do_build=do_build)
  File "/usr/lib/python2.7/site-packages/compose/service.py", line 311, in ensure_image_exists
    self.pull()
  File "/usr/lib/python2.7/site-packages/compose/service.py", line 1024, in pull
    output = self.client.pull(repo, tag=tag, stream=True)
  File "/usr/lib/python2.7/site-packages/docker/api/image.py", line 381, in pull
    header = auth.get_config_header(self, registry)
AttributeError: 'module' object has no attribute 'get_config_header'

It looks like it's because docker-py is currently being installed, instead of just docker (via pip). See docker/docker-py#1353 (comment)