Add molecule tests for rke role

This change adds molecule tests for the rke role, and
modifies the rke role itself to be more idempotent/to
pass linter.
Note that this molecule test case uses a separate
role to install docker in containers, that runs
docker daemon inside of them instead of using host docker.

Issue-ID: OOM-1778
Change-Id: I875f3ff2ab961e5428acee5a02287a8d2d6e9969
Signed-off-by: Michal Zegan <m.zegan@samsung.com>
diff --git a/ansible/test/roles/prepare-rke/tasks/main.yml b/ansible/test/roles/prepare-rke/tasks/main.yml
new file mode 100644
index 0000000..210c9b5
--- /dev/null
+++ b/ansible/test/roles/prepare-rke/tasks/main.yml
@@ -0,0 +1,2 @@
+---
+- include_tasks: "{{ mode }}.yml"