Put 'policy' out of params for do_cluster_policy_attach

In openstackSDK cluster_attach_policy method has 'cluster'
and 'policy' parameters out of **params, so senlinclient
should do the same thing for calling SDK.

Change-Id: I18d3c499467daf371f64c2a883af7c710d16db87
Closes-bug: #1530751

senlinclient/tests/unit/v1/test_shell.py

@@ -1014,7 +1014,6 @@ class ShellTest(testtools.TestCase):
         }
         args = self._make_args(args)
         kwargs = {
-            'policy_id': 'policy1',
             'priority': 50,
             'level': 60,
             'cooldown': 120,
@@ -1024,7 +1023,7 @@ class ShellTest(testtools.TestCase):
         client.conn.cluster.cluster_attach_policy.return_value = resp
         sh.do_cluster_policy_attach(client, args)
         client.conn.cluster.cluster_attach_policy.assert_called_once_with(
-            'cluster1', **kwargs)
+            'cluster1', 'policy1', **kwargs)
 
     def test_do_cluster_policy_detach(self):
         args = {

senlinclient/v1/shell.py

@@ -782,14 +782,14 @@ def do_cluster_policy_show(sc, args):
 def do_cluster_policy_attach(sc, args):
     """Attach policy to cluster."""
     kwargs = {
-        'policy_id': args.policy,
         'priority': args.priority,
         'level': args.enforcement_level,
         'cooldown': args.cooldown,
         'enabled': args.enabled,
     }
 
-    resp = sc.conn.cluster.cluster_attach_policy(args.id, **kwargs)
+    policy = args.policy
+    resp = sc.conn.cluster.cluster_attach_policy(args.id, policy, **kwargs)
     print('Request accepted by action: %s' % resp['action'])