docker_swarm: fix diff mode and details (#53053)

* Fix diff messages for leaving swarm.

* Remove superfluous brakets.

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

@@ -434,7 +434,7 @@ class SwarmManager(DockerBaseClass):
                 self.client.fail("Swarm not created or other error!")
         self.inspect_swarm()
         self.results['actions'].append("New Swarm cluster created: %s" % (self.swarm_info.get('ID')))
-        self.differences.add('state', parameter='absent', active='present')
+        self.differences.add('state', parameter='present', active='absent')
         self.results['changed'] = True
         self.results['swarm_facts'] = {u'JoinTokens': self.swarm_info.get('JoinTokens')}
 
@@ -480,7 +480,7 @@ class SwarmManager(DockerBaseClass):
         self.results['changed'] = True
 
     def leave(self):
-        if not(self.client.check_if_swarm_node()):
+        if not self.client.check_if_swarm_node():
             self.results['actions'].append("This node is not part of a swarm.")
             return
         if not self.check_mode:
@@ -493,7 +493,7 @@ class SwarmManager(DockerBaseClass):
         self.results['changed'] = True
 
     def remove(self):
-        if not(self.client.check_if_swarm_manager()):
+        if not self.client.check_if_swarm_manager():
             self.client.fail("This node is not a manager.")
 
         try: