setZoom animation doesn't work anymore

[tidemann]

Tried setting up http://tombatossals.github.io/angular-openlayers-directive/examples/023-center-constrain-zoom-example.html, but it seems the zoom animation isn't working anymore.

See plunker here:
https://plnkr.co/edit/NivlfAOqZoOF3tTw8FOR?p=preview