Fix idempotency issue in 'prepare-docker' role

This adds 'creates' arg to 'command' module used in
the role scope.

Change-Id: Ib500680114fb267cc08ab52f09fa691738ea4a1a
Issue-ID: OOM-1850
Signed-off-by: Bartek Grzybowski <b.grzybowski@partner.samsung.com>
diff --git a/ansible/test/roles/prepare-docker/tasks/docker-packages.yml b/ansible/test/roles/prepare-docker/tasks/docker-packages.yml
index b7e76c5..1239e1a 100644
--- a/ansible/test/roles/prepare-docker/tasks/docker-packages.yml
+++ b/ansible/test/roles/prepare-docker/tasks/docker-packages.yml
@@ -2,6 +2,8 @@
 
 - name: Download docker related packages
   command: yumdownloader --destdir="{{ rpm_dir }}" "{{ docker_ce_rpm }}" "{{ docker_ce_selinux_rpm }}"
+  args:
+    creates: "{{ rpm_dir }}/{{ docker_ce_selinux_rpm }}"
 
 - name: Install docker related packages
   yum: