Created Unassigned: Bug in Open Generics with IBiz [14615]

In the code below x gets 0 results but it should get one.

```
class Program
{
static void Main(string[] args)
{
var cat = new AssemblyCatalog(typeof (Program).Assembly);
var con = new CompositionContainer(cat);
var x = con.GetExportedValues<Buz<int>>();
}
}

interface IBiz<T, U> { }

[Export(typeof(IBiz<,>))]
class Biz<T, U> : IBiz<T, U> { }

[Export(typeof(Buz<>))]
class Buz<T>
{
public IBiz<T, int> Biz { get; private set; }

[ImportingConstructor]
public Buz(IBiz<T, int> biz)
{
Biz = biz;
}
}
```