Make Cesium work again on the Nexus 4

Cesium recently stopped working with my Nexus 4, possibly when it upgraded to Android 4.3.  This fixes it.  The problem is that the device was reporting a strange uniform with the name `webgl_3467e0265d05c3c1[1]`.  It's just making stuff up, apparently.  My change just ignores the mysterious uniform and all is well.