Same thing on Ubuntu 16.04. Same exact error, exact same versions.
I had a working setup a week or two ago, just came back to it and I get the error described above. I assume a new version of docker was installed without my paying attention.
The entire list of docker-related packages on my system:
ii docker.io 1.11.2-0ubuntu5~16.04 amd64 Linux container runtime
ii python-docker 1.8.0-0ubuntu1 all Python wrapper to access docker.io’s control socket
ii python-dockerpty 0.3.4-1build1 all Pseudo-tty handler for docker Python client (Python 2.x)
ii vim-syntax-docker 1.11.2-0ubuntu5~16.04 all Docker container engine - Vim highlighting syntax files
env | grep DOCKER gets nothing. There are no docker-related variables in any of my .bash* files.
I would love to know how to get this working again.