The CI system requires that some environment variables are set so merge
our variables into the current environment instead of blindly replacing
it.
This will probably have to be repeated for other tests. C'est la vie.
Fix the following exception:
http.js:974
this._httpMessage.emit('close');
^
TypeError: Cannot call method 'emit' of null
at Socket.onServerResponseClose (http.js:974:21)
at Socket.EventEmitter.emit (events.js:124:20)
at net.js:421:10
at process._tickCallback (node.js:386:13)
at process._makeCallback (node.js:304:15)
Fixes#4586.