paas were trying to ascertain if notify was up by looking at '/', for cert
renewal. This commit adds the status endpoint to '/', so we're not mistakenly
left for our cert to expire
The test this status check was doing does not reflect real traffic of Notify. It is typical for messages to be in 'sending' for a while (people turn off their phone for example).
If the notification ends up in the retry queue and the delivery app is restarted the notification will get sent twice.
This is because when the app is restarted another message will be in the retry queue as message available which is a
duplicate of the one in the queue that is a message in flight.
This should complete https://www.pivotaltracker.com/story/show/121844427
