Upgrade docker SDK for python during overcloud host upgrade

Kolla-ansible requires use of the docker python package, which is
incompatible with the legacy docker-py python package. We install the
former and remove the latter.

ansible/overcloud-docker-sdk-upgrade.yml

@@ -0,0 +1,18 @@
+---
+- name: Ensure docker SDK for python is installed
+  hosts: overcloud
+  tasks:
+    # Docker renamed their python SDK from docker-py to docker in the 2.0.0
+    # release, and also broke backwards compatibility. Kolla-ansible requires
+    # docker, so ensure it is installed.
+    - name: Ensure legacy docker-py python package is uninstalled
+      pip:
+        name: docker-py
+        state: absent
+      become: True
+
+    - name: Ensure docker SDK for python is installed
+      pip:
+        name: docker
+        state: latest
+      become: True

kayobe/cli/commands.py

@@ -490,7 +490,7 @@ class OvercloudHostUpgrade(KollaAnsibleMixin, KayobeAnsibleMixin, VaultMixin,
     def take_action(self, parsed_args):
         self.app.LOG.debug("Upgrading overcloud host services")
         playbooks = _build_playbook_list(
-            "overcloud-etc-hosts-fixup")
+            "overcloud-docker-sdk-upgrade", "overcloud-etc-hosts-fixup")
         self.run_kayobe_playbooks(parsed_args, playbooks)