VS2017 RC - script options are never updated


This is the issue fixed by https://github.com/Microsoft/visualfsharp/pull/1865

#### Repro steps

Take a script

```
//#r "Foo.dll"

let x = Foo.UseSomething()
```

Uncomment the ``#r``.  

#### Expected behavior

The red squiggly disappears (because the project options have now been updated)


#### Actual behavior

The red squiggly does not disappear

