Always clear cached facts first

Because you could be running against different clouds or hosts, we need
to always clear the facts at the start of the deployment playbook to
ensure we aren't using incorrectly cached facts. That being said, the
caching mechanism should persist between the plays in the overall
deployment.

Change-Id: I5992edf43bf1995eebdf401c6bd886e77e528695
Closes-Bug: #1884654

common/deploy-steps-playbooks-common.yaml

@@ -1,3 +1,8 @@
+- hosts: all
+  name: Clear cached facts
+  tasks:
+    - meta: clear_facts
+
 - hosts: "{{ deploy_source_host }}"
   name: Gather facts from undercloud
   gather_facts: yes