Replace docker-py with docker

docker-py's last release is outdated[0], last updated Nov 2016 while
the more up-to-date "docker" release[1] is still maintained. This
changes the use of "docker-py" to "docker".

[0] https://pypi.org/project/docker-py/
[1] https://pypi.org/project/docker/

Change-Id: I78fe5e426631c5ea5e0d128dc30fd55c81cca2e0

roles/deploy-docker/tasks/deploy-ansible-docker-support.yaml

@@ -54,4 +54,4 @@
     tasks_from: pip
   vars:
     packages:
-      - docker-py
+      - docker