compute: host: expand kwargs in host_set() call

`host_set()` expects `status` and `maintenance_mode` as keyword
arguments, but in `SetHost.take_action()`, it is called without
expanding the keyword arguments.

So it's called as

```
host_set(host, {'status': 'enable'})
```

instead of

```
host_set(host, status='enable')
```

Change-Id: If0b37ac60091161a892bfc694fce31a988f66005
Task: 23023

openstackclient/compute/v2/host.py

@@ -97,7 +97,7 @@ class SetHost(command.Command):
 
         compute_client.api.host_set(
             parsed_args.host,
-            kwargs
+            **kwargs
         )
 
 

openstackclient/tests/unit/compute/v2/test_host.py

@@ -111,8 +111,7 @@ class TestHostSet(TestHost):
         result = self.cmd.take_action(parsed_args)
         self.assertIsNone(result)
 
-        body = {}
-        h_mock.assert_called_with(self.host['host'], body)
+        h_mock.assert_called_with(self.host['host'])
 
     def test_host_set(self, h_mock):
         h_mock.return_value = self.host
@@ -133,8 +132,8 @@ class TestHostSet(TestHost):
         result = self.cmd.take_action(parsed_args)
         self.assertIsNone(result)
 
-        body = {'status': 'enable', 'maintenance_mode': 'disable'}
-        h_mock.assert_called_with(self.host['host'], body)
+        h_mock.assert_called_with(self.host['host'], status='enable',
+                                  maintenance_mode='disable')
 
 
 @mock.patch(