notifications for exist event are sent when the state is 'build'

[Craig Vyvial]

Now that exist notifications are working better in the master branch, I noticed that they are sent even when the instance is in a 'build' state. This might not seem useful since the create event has not occurred yet.

Example log data:
https://gist.githubusercontent.com/cp16net/f49b85f3221a977f5046/raw/8f6080bbe6d3679a509e5d4b6a6f6192bbfe99ca/gistfile1.txt

Thinking out loud here...
Maybe this would be more useful if there was an initial trove.instance.build state.
I think we should talk about use cases if this makes sense or not.