Cleanup the push-docker role and add some comment about the role

Signed-off-by: Clement Verna <cverna@tutanota.com>

roles/push-docker/tasks/main.yml

@@ -1,16 +1,12 @@
 ---
-# tasks file for push-docker
-#
+# tasks file for push-docker role
+# This role is used to login to a registry using the
+# docker client.
+
 - name: install docker and python-docker
   package: name="{{ item }}" state=present
   with_items:
     - docker
-    - python-docker
-
-- name: ensure docker daemon cert dir exists
-  file:
-    path: "{{docker_cert_dir}}"
-    state: directory
 
 - name: start and enable docker
   service: name=docker state=started enabled=yes