send maintenance_window.hour even if it's zero, since that's a valid value

Author: danawillow

google/resource_sql_database_instance.go

@@ -594,9 +594,10 @@ func expandMaintenanceWindow(configured []interface{}) *sqladmin.MaintenanceWind
 
 	window := configured[0].(map[string]interface{})
 	return &sqladmin.MaintenanceWindow{
-		Day:         int64(window["day"].(int)),
-		Hour:        int64(window["hour"].(int)),
-		UpdateTrack: window["update_track"].(string),
+		Day:             int64(window["day"].(int)),
+		Hour:            int64(window["hour"].(int)),
+		UpdateTrack:     window["update_track"].(string),
+		ForceSendFields: []string{"Hour"},
 	}
 }