Ensure kolla virtualenv contains docker package rather than docker-py

This allows the virtualenv to be reused following an upgrade.

ansible/roles/kolla/tasks/install.yml

@@ -46,7 +46,7 @@
   pip:
     name: "{{ item.name }}"
     version: "{{ item.version | default(omit) }}"
-    state: present
+    state: "{{ item.state | default('present') }}"
     virtualenv: "{{ kolla_venv }}"
   with_items:
     # Intall Kolla from source.
@@ -59,4 +59,9 @@
     # Required for kolla-genpwd.
     - name: PyYAML
       version: "3.12"
+    # In version 2.0.0, docker renamed the docker-py python package to docker.
+    # Kolla requires the docker package rather than the docker-py package.
+    - name: docker-py
+      state: absent
+    - name: docker
   when: "{{ item.install | default(True) | bool }}"