Install docker-compose using pip

Change-Id: I9fe62b1d0501c8fd25c5bd210a423a5d8c41922f

playbooks/docker/pre.yaml

@@ -3,6 +3,7 @@
 - hosts: all
   roles:
     - role: ensure-docker
+    - role: tobiko-ensure-python3
     - role: tobiko-ensure-docker-compose
     - role: tobiko-docker-compose
       vars:

roles/tobiko-ensure-docker-compose/defaults/main.yaml

@@ -1,3 +1,5 @@
 ---
 
 docker_compose_executable: /usr/local/bin/docker-compose
+docker_compose_install_using_pip: true
+docker_compose_install_using_curl: not docker_compose_install_using_pip

roles/tobiko-ensure-docker-compose/tasks/main.yaml

@@ -1,6 +1,14 @@
 ---
 
-- name: "Install latest Docker compose"
+- name: "Install latest Docker compose with Pip"
+  become: true
+  shell: |
+    set -x
+    python3 -m pip install docker-compose
+  when: docker_compose_install_using_pip
+
+
+- name: "Install latest Docker compose with Curl"
   become: true
   shell: |
     set -x
@@ -15,3 +23,4 @@
     mkdir -p $(dirname '{{ docker_compose_executable }}')
     curl -L ${URL} > '{{ docker_compose_executable }}'
     chmod +x '{{ docker_compose_executable }}'
+  when: docker_compose_install_using_curl