Update calling-a-web-api-from-a-net-client.md (dotnet#155)

* Update calling-a-web-api-from-a-net-client.md

The URL download instructions is broken. I've searched and found the correct URL. I'm uploading here in order to help other who have the same issue.

* Remove version from URL

aspnet/web-api/overview/advanced/calling-a-web-api-from-a-net-client.md

@@ -159,7 +159,7 @@ Like GET, a DELETE request does not have a request body. You don't need to speci
 
 To test the client app:
 
-1. [Download](https://github.com/aspnet/AspNetDocs/tree/master/aspnet/web-api/overview/advanced/calling-a-web-api-from-a-net-client/sample/server) and run the server app. [Download instructions](/aspnet/core/tutorials/#how-to-download-a-sample). Verify the server app is working. For example, `http://localhost:64195/api/products` should return a list of products.
+1. [Download](https://github.com/aspnet/AspNetDocs/tree/master/aspnet/web-api/overview/advanced/calling-a-web-api-from-a-net-client/sample/server) and run the server app. [Download instructions](/aspnet/core/#how-to-download-a-sample). Verify the server app is working. For example, `http://localhost:64195/api/products` should return a list of products.
 2. Set the base URI for HTTP requests. Change the port number to the port used in the server app.
     [!code-csharp[Main](calling-a-web-api-from-a-net-client/sample/client/Program.cs?name=snippet5&highlight=2)]