So I found this on the apple dev forums from an Apple engineer (https://devforums.apple.com/message/1059332#1059332).
Another developer wrote in to DTS and thus I had a chance to investigate this in depth. Alas, the news is much as I expected: there is no supported way to detect that your app is in this state. Nor is there a way to make a "no user interaction" network connection, that is, request that the connection fail rather than present UI like this. If these limitations are causing problems for your app, I encourage you to file a bug describing your specific requirements.
https://developer.apple.com/bug-reporting/
So it looks like it is not possible to detect if cellular data for your app has been turned off.
Edit
I filed a radar for this requesting that it be added. I just got this notification in my radar
We believe this issue has been addressed in the latest iOS 9 beta.
I looked through the API diffs, but so far I can't find the new API.