Pinch zoom broken for iPhone and iPad

[hpinkos]

Reported on the forum: https://groups.google.com/forum/?hl=en#!topic/cesium-dev/5VarapsvvdA

Load the code then pinch to zoom. This will cause a crash

var viewer = new Cesium.Viewer('cesiumContainer');

var dblInitLon = -117.72456;
var dblInitLat = 33.06154;
var dblInitAlt = 342418.4;
var dblHeading = 0;
viewer.scene.camera.setView({
    destination: Cesium.Cartesian3.fromDegrees(dblInitLon, dblInitLat, dblInitAlt),
    orientation: {
        heading: Cesium.Math.toRadians(dblHeading),
        pitch: Cesium.Math.toRadians(-90),
        roll: 0.0
    }
});

[mramato]

Is this a dupe of #4177?

[hpinkos]

"If I move the scene first and then zoom everything works fine."

Yes, this does look like a dupe of #4177