Fix for failing component unmount test

[wolfflow]

Test failure detected while running jasmine specs with latest Bacon.js (0.7.30)

Testing jasmine specs via PhantomJS BaconMixin #eventStream - returns the stream for that defined name......√ - returns always the same event stream......√ - defines a function property with the name of the stream......√ - that defined function can be used as event handler, and pushes to the stream......√ - removes subscribers when the component unmounts......× TypeError: 'undefined' is not a function (evaluating 'stream.hasSubscribers()') in /project/node_modules/react-bacon/tmp/specs.js (line 22246) (1)