Fix element miss in client request body

Currently the client sends a request with wrong element name
'os-multiple-create:reservation_id' in the body.
The correct element should be 'os-multiple-create:return_reservation_id'.
The information can be got in this website.
https://wiki.openstack.org/wiki/NovaAPIv2tov3

Change-Id: I7d2f006ef6dbbcd6b41c8adbeee0c0e048d35448
Closes-Bug: #1281342

novaclient/tests/v3/test_servers.py

@@ -121,6 +121,26 @@ class ServersTest(utils.TestCase):
         cs.assert_called('POST', '/servers')
         self.assertIsInstance(s, servers.Server)
 
+    def test_create_server_return_reservation_id(self):
+        s = cs.servers.create(
+            name="My server",
+            image=1,
+            flavor=1,
+            reservation_id=True
+        )
+        expected_body = {
+            'server': {
+                'name': 'My server',
+                'image_ref': '1',
+                'flavor_ref': '1',
+                'os-multiple-create:min_count': 1,
+                'os-multiple-create:max_count': 1,
+                'os-multiple-create:return_reservation_id': True,
+            }
+        }
+        cs.assert_called('POST', '/servers', expected_body)
+        self.assertIsInstance(s, servers.Server)
+
     def test_update_server(self):
         s = cs.servers.get(1234)
 

novaclient/v3/servers.py

@@ -409,7 +409,7 @@ class ServerManager(base.BootingManagerWithFind):
             body["server"]["metadata"] = meta
         if reservation_id:
             body["server"][
-                "os-multiple-create:reservation_id"] = reservation_id
+                "os-multiple-create:return_reservation_id"] = reservation_id
         if key_name:
             body["server"]["key_name"] = key_name
         if scheduler_hints: