Modify rancher molecule tests to use dind

This change modifies molecule tests of rancher role to
use prepare-docker-dind.
Also:
- it modifies prepare-common role to retrieve cluster_ip of the actual
node in question,
- it fixes the rancher role itself to work at all by removing auto_remove.
It has been tested by running molecule converge.

Change-Id: I7af4e9998feedd5f8fc3df8215e03c1b0485529c
Issue-ID: OOM-1864
Signed-off-by: Michal Zegan <m.zegan@samsung.com>
diff --git a/ansible/roles/rancher/molecule/default/prepare.yml b/ansible/roles/rancher/molecule/default/prepare.yml
index 90159c6..d70cda4 100644
--- a/ansible/roles/rancher/molecule/default/prepare.yml
+++ b/ansible/roles/rancher/molecule/default/prepare.yml
@@ -1,5 +1,5 @@
 ---
-- name: Prepare kube nodes
-  hosts: kubernetes
+- name: Prepare hosts
+  hosts: all
   roles:
-    - prepare-docker
+    - prepare-docker-dind