updating: reflip gate properly uses check || self.exportsName

I noticed while trying to implement this, if some starts up a `Reflip({ exportsName: 'checkSolarSailer'})` for example, the `reflip.gate()` method does not seem to work properly.

Since there is a default upon instantiation of either `options.exportName || 'check'` I figured this was a safe update patch, and not breaking. But I do not fully understand this module, I just know this fixes the issue I am working around currently ;)

Also, all tests seem to past except the `coveralls` one - not sure whats up there.