Abortion is not being performed on the controller

[acontreras89]

Request controllers (as returned by network adapters) expose an abort method which is supposed to be used to interrupt the underlying request. See superagent adapter for an example.

However, since the addition of the instance prop (e4b33fb) this controller is no longer stored in the state, and instead its instance is.

This causes the middleware to call .abort() on the wrong object.