Handle undercloud autostart dependant on ansible version

On ansible version lower than 2.3:
 1.- Start undercloud vm
 2.- Make the vm automatically start

On ansible version equal or grater than 2.3:
 1.- Start the undercloud vm and make it automatically start

Change-Id: I57168f15d63f638bd0217955a3a3c245a986c541
Closes-bug: #1689620

roles/libvirt/setup/undercloud/tasks/main.yml

@@ -301,21 +301,35 @@
     state: 'directory'
   when: non_root_chown|bool
 
-# Start the undercloud virtual machine.
+# This block only run when ansible version < 2.3.
+- block:
+    # Start the undercloud virtual machine.
+    - name: Start undercloud vm
+      virt:
+        name: "{{ undercloud_node.name }}"
+        command: start
+        state: running
+        uri: "{{ libvirt_uri }}"
+
+    # Configure the undercloud virtual machine to be
+    # automatically started at boot.
+    - name: Configure undercloud vm to start at virthost boot
+      virt:
+        name: "{{ undercloud_node.name }}"
+        command: autostart
+        uri: "{{ libvirt_uri }}"
+  when: "{{ ansible_version.full | version_compare('2.3','<') }}"
+
+# Start the undercloud virtual machine and make it
+# automatically start for ansible-version >= 2.3
 - name: Start undercloud vm
   virt:
     name: "{{ undercloud_node.name }}"
     command: start
+    autostart: true
     state: running
     uri: "{{ libvirt_uri }}"
-
-# Configure the undercloud virtual machine to be
-# automatically started at boot.
-- name: Configure undercloud vm to start at virthost boot
-  virt:
-    name: "{{ undercloud_node.name }}"
-    command: autostart
-    uri: "{{ libvirt_uri }}"
+  when: "{{ ansible_version.full | version_compare('2.3','>=') }}"
 
 # Get the ip address of the undercloud.  This will retry several times
 # (`undercloud_ip_retries`) until the undercloud is ready.  The script