Get installation working on CentOS, add Debian 8 test.

tasks/setup-RedHat.yml

@@ -1,13 +1,13 @@
 ---
-# - name: Add Docker GPG key.
-#   rpm_key:
-#     key: https://apt.dockerproject.org/gpg
-#     state: present
+- name: Add Docker GPG key.
+  rpm_key:
+    key: https://yum.dockerproject.org/gpg
+    state: present
 
 - name: Add Docker repository.
-  yum_repository:
-    name: docker
-    description: Docker repository.
-    baseurl: https://docs.docker.com/engine/installation/linux/repo_files/centos/docker.repo
-    gpgkey: https://apt.dockerproject.org/gpg
-    gpgcheck: yes
+  template:
+    src: 'docker.repo.j2'
+    dest: '/etc/yum.repos.d/docker.repo'
+    owner: root
+    group: root
+    mode: 0644