[Mono.Posix] Adding missing file to clean target of Makefile
[Mono.Posix] Adding missing file to clean target of Makefile

xamarin/XamarinComponents,bholmes/XamarinComponents,xamarin/XamarinComponents,bholmes/XamarinComponents,xamarin/XamarinComponents,xamarin/XamarinComponents,xamarin/XamarinComponents,bholmes/XamarinComponents,bholmes/XamarinComponents,bholmes/XamarinComponents,xamarin/XamarinComponents,bholmes/XamarinComponents