No longer rely on HttpContext.AddError to forward Web API exceptions to SerilogWeb module

Instead rely on ad-hoc extension method that stores it temporarily in HttpContext

Related to #16 and #3

Author: tsimbalar

src/SerilogWeb.Classic.WebApi/Classic/WebApi/WebApiExceptionLogger.cs

@@ -1,13 +1,17 @@
 using System.Web;
 using System.Web.Http.ExceptionHandling;
+using SerilogWeb.Classic.Extensions;
 
 namespace SerilogWeb.Classic.WebApi
 {
     public class WebApiExceptionLogger : ExceptionLogger
     {
         public override void Log(ExceptionLoggerContext context)
         {
-            HttpContext.Current.AddError(context.Exception);
+            if (context.Exception != null)
+            {
+                HttpContext.Current.AddSerilogWebError(context.Exception);
+            }
         }
     }
 }