[svn r328] Fixed an issue with interfaces where the vtable type of a interface implemented could be invalid. Fixes several tango modules like, FileStream, ServerSocket and most tina cluster modules :)

module tangotests.debug9;

struct Foo
{
    int a,b,c;

    void func()
    {
        int* fail;
        *fail = 0;
    }
}

void main()
{
    Foo foo = Foo(1,10,73);
    foo.func();
}