copy callback property to the web request

Author: cogree

RestSharp/Http.Async.cs

@@ -485,6 +485,9 @@ private HttpWebRequest ConfigureAsyncWebRequest(string method, Uri url)
 
 #if !SILVERLIGHT
             webRequest.AllowAutoRedirect = this.FollowRedirects;
+#endif
+#if NET45
+            webRequest.ServerCertificateValidationCallback = this.RemoteCertificateValidationCallback;
 #endif
             return webRequest;
         }

RestSharp/Http.Sync.cs

@@ -312,6 +312,10 @@ private HttpWebRequest ConfigureWebRequest(string method, Uri url)
                 webRequest.MaximumAutomaticRedirections = this.MaxRedirects.Value;
             }
 
+#if NET45
+            webRequest.ServerCertificateValidationCallback = this.RemoteCertificateValidationCallback;
+#endif
+
             return webRequest;
         }
     }