add various fixes
diff --git a/openstack/db/v1/instances/fixtures.go b/openstack/db/v1/instances/fixtures.go
index 9b4b209..1388e23 100644
--- a/openstack/db/v1/instances/fixtures.go
+++ b/openstack/db/v1/instances/fixtures.go
@@ -89,7 +89,7 @@
 )
 
 var (
-	restartReq   = `{"restart": true}`
+	restartReq   = `{"restart": {}}`
 	resizeReq    = `{"resize": {"flavorRef": "2"}}`
 	resizeVolReq = `{"resize": {"volume": {"size": 4}}}`
 )
diff --git a/openstack/db/v1/instances/requests.go b/openstack/db/v1/instances/requests.go
index bd70295..425db13 100644
--- a/openstack/db/v1/instances/requests.go
+++ b/openstack/db/v1/instances/requests.go
@@ -179,7 +179,7 @@
 	var res ActionResult
 
 	_, res.Err = client.Request("POST", actionURL(client, id), gophercloud.RequestOpts{
-		JSONBody: map[string]interface{}{"restart": true},
+		JSONBody: map[string]interface{}{"restart": struct{}{}},
 		OkCodes:  []int{202},
 	})