Fix warnings

Author: dsrodenas

src/Services/Ordering/Ordering.Domain/AggregatesModel/BuyerAggregate/PaymentMethod.cs

@@ -7,7 +7,6 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.AggregatesModel.B
     public class PaymentMethod
         : Entity
     {
-        private int _buyerId;
         private string _alias;
         private string _cardNumber;
         private string _securityNumber;

src/Services/Ordering/Ordering.Domain/AggregatesModel/OrderAggregate/OrderItem.cs

@@ -12,7 +12,6 @@ public class OrderItem
         // aligned with DDD Aggregates and Domain Entities (Instead of properties and property collections)
         private string  _productName;
         private string  _pictureUrl;
-        private int     _orderId;
         private decimal _unitPrice;
         private decimal _discount;
         private int     _units;

src/Web/WebMVC/Controllers/OrderController.cs

@@ -49,7 +49,7 @@ public async Task<IActionResult> Create(Order model, string action)
                     return RedirectToAction("Index");
                 }
             }
-            catch(BrokenCircuitException ex)
+            catch(BrokenCircuitException)
             {
                 ModelState.AddModelError("Error", "It was not possible to create a new order, please try later on");
             }