Closed Issue: Request dispatched to incorrect action resulting in 400 Bad Request [1233]

A request for '/api/customers' is resulting in 400 Bad Request.

__Attached__ a katana selfhost repro.

__Reason__:
The problem seems to be happening because of the following piece of code in RouteCollectionRouteData. Here we are assigning empty string to the keys. For the above request the matching route template would be "api/customers/{id}" and this piece of code would assign a value of "" to 'id' variable. This is problematic as the step of "RemoveOptionalRoutingParameters(routeData.Values);" in HttpRoutingDispatcher wouldn't work as expected.

```
public IDictionary<string, object> Values
{
get
{
// Keys is just a union of the Keys from the sub routes.
// We don't actually use the values, because different subroutes may have conflicting values.
// Action selection just needs to know which keys are present.
if (_values == null)
{
var dict = new HttpRouteValueDictionary();
foreach (var data in SubRouteDatas)
{
foreach (var kv in data.Values)
{
// Actual value doesn't matter. We just look for the presence of the key.
dict[kv.Key] = String.Empty;
}
}
dict[SubRouteDataKey] = SubRouteDatas;

_values = dict;
}

return _values;
}
}
```

__Error__:
```
StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Date: Tue, 20 Aug 2013 19:44:39 GMT
Server: Microsoft-HTTPAPI/2.0
Content-Length: 350
Content-Type: application/json; charset=utf-8
}
{"Message":"The request is invalid.","MessageDetail":"The parameters dictionary contains a null entry for parameter 'id'
of non-nullable type 'System.Int32' for method 'System.String GetCustomer(Int32)' in 'SampleOwinApp.CustomersController
'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter."}
```

__Controller__:
```
[RoutePrefix("api/customers")]
[Route("{id?}")]
public class CustomersController : ApiController
{
public string GetAllCustomers()
{
return "GetAllCustomers";
}

public string GetCustomer(int id)
{
return "GetCustomer:" + id;
}

public string CreateCustomer([FromBody]string value)
{
return "CreateCustomer:" + value;
}

[HttpPut]
public string UpdateCustomer(int id, [FromBody]string value)
{
return "UpdateCustoemr:" + id + ":" + value;
}

public string DeleteCustomer(int id)
{
return "DeleteCustomer:" + id;
}

[Route("{id}/orders")]
public string GetOrdersOfCustomer(int id)
{
return "GetOrdersOfCustomer:" + id;
}
}
```
Comments: Verified.