fix replace VNode with VText

87b9ad36fd72548bf60f62eaa0db130fd6f869d5 broke the following test:

```js
test("Can replace vnode with vtext", function (assert) {

    var leftNode = h("div", h("div"))
    var rightNode = h("div", "text")

    var rootNode = render(leftNode)

    assert.equal(rootNode.childNodes.length, 1)
    assert.equal(rootNode.childNodes[0].nodeType, 1)

    var patches = diff(leftNode, rightNode)

    var newRoot = patch(rootNode, patches)

    assert.equal(newRoot, rootNode)

    assert.equal(newRoot.childNodes.length, 1)
    assert.equal(newRoot.childNodes[0].nodeType, 3)

    assert.end()
})
```

Was caused by missing `apply = appendPatch(apply, new VPatch(VPatch.VTEXT, a, b))` on VText patch handler

This PR puts it back!