[2.7] docker_swarm_service: fix problem with UpdateConfig on certain docker daemons (#53224)

* Avoid KeyError when UpdateConfig isn't returned.

* Add changelog.

changelogs/fragments/53224-docker_swarm_service-UpdateConfig.yml

@@ -0,0 +1,2 @@
+bugfixes:
+- "docker_swarm_service - fix problem with docker daemons which do not return ``UpdateConfig`` in the swarm service spec."

lib/ansible/modules/cloud/docker/docker_swarm_service.py

@@ -897,12 +897,14 @@ class DockerServiceManager():
         ds = DockerService()
 
         task_template_data = raw_data['Spec']['TaskTemplate']
-        update_config_data = raw_data['Spec']['UpdateConfig']
 
         ds.image = task_template_data['ContainerSpec']['Image']
         ds.user = task_template_data['ContainerSpec'].get('User', 'root')
         ds.env = task_template_data['ContainerSpec'].get('Env', [])
         ds.args = task_template_data['ContainerSpec'].get('Args', [])
+
+        update_config_data = raw_data['Spec'].get('UpdateConfig')
+        if update_config_data:
             ds.update_delay = update_config_data['Delay']
             ds.update_parallelism = update_config_data['Parallelism']
             ds.update_failure_action = update_config_data['FailureAction']