Assert container's ssl cert exists before upgrade.

While performing upgrade from Q to R undercloud is switched
from non-containerized to containerized, so some kolla* specific
dirs/files might not exist.
This change adds asserts if that dirs exis before manipulating
them.

Change-Id: I0fe99cc5cd10c7f78798e31435058908d0184973

puppet/services/haproxy-public-tls-inject.yaml

@@ -180,11 +180,19 @@ outputs:
                 - name: set kolla_dir fact
                   set_fact: kolla_dir="/var/lib/kolla/config_files/src-tls"
 
+                - name: assert {{ kolla_dir }}{{ cert_path }} exists
+                  stat:
+                    path: "{{ kolla_dir }}{{cert_path}}"
+                  register: kolla_cert_exists
+
                 - name: set certificate group on host via container
                   command: docker exec {{container_id.stdout}} chgrp haproxy {{kolla_dir}}{{cert_path}}
+                  when: kolla_cert_exists.stat.exists
 
                 - name: copy certificate from kolla directory to final location
                   command: docker exec {{container_id.stdout}} cp {{kolla_dir}}{{cert_path}} {{cert_path}}
+                  when: kolla_cert_exists.stat.exists
 
                 - name: send restart order to haproxy container
                   command: docker kill --signal=HUP {{container_id.stdout}}
+                  when: kolla_cert_exists.stat.exists