App sometimes crashes if exclusive split traffic doesn't total 100%

[tandrewnichols]

If you, for instance, define traffic as

"foo": {
  "exclusiveSplit": true,
  "traffic": 1,
  "features": {
    "a": {
      "traffic": 0.33
    },
    "b": {
      "traffic": 0.33
    },
    "c": {
      "traffic": 0.33
    }
  }
}

We've observed that this typically throws "Cannot read property 'isFeatureEnabled' of undefined" somewhere in our routes/middleware. This might not be only with exclusiveSplits . . . it might be when the inner traffic does not add up to the parent traffic.