[Bug] Query ref does not works in scoped models

[IAkumaI]

1. Create some component

import {Component} from 'derby';

export class MyComp extends Component {
    static readonly is = 'my-comp';
    static readonly view = __dirname;

    create() {
        let $query = this.model.query('collection', {query:1});
        $query.subscribe();
        $query.ref('list'); // Now list will always empty array, but $query.get() contains items

        let $query = this.model.root.query('collection', {query:1});
        $query.subscribe();
        this.model.ref('list', $query); // But root-variant works
    }
}