Move memcached precheck into its own role

Change-Id: Ib14471c9cdbd3dee000594d3ca87a6c0b487ad3e
Partially-implements: blueprint condition-pre-check

ansible/roles/memcached/tasks/precheck.yml

 ---
+- name: Get container facts
+  kolla_container_facts:
+    name:
+      - memcached
+  register: container_facts
+
+- name: Checking free port for Memcached
+  wait_for:
+    host: "{{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}"
+    port: "{{ memcached_port }}"
+    connect_timeout: 1
+    state: stopped
+  when:
+    - container_facts['memcached'] is not defined
+    - inventory_hostname in groups['memcached']

ansible/roles/prechecks/tasks/port_checks.yml

@@ -377,16 +377,6 @@
     - enable_mariadb | bool
     - inventory_hostname in groups['mariadb']
 
-- name: Checking free port for Memcached
-  wait_for:
-    host: "{{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}"
-    port: "{{ memcached_port }}"
-    connect_timeout: 1
-    state: stopped
-  when:
-    - enable_memcached | bool
-    - inventory_hostname in groups['memcached']
-
 - name: Checking free port for Murano API
   wait_for:
     host: "{{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}"