charm push allows pushing of a charm that's not been built

[mitechie]

It should detect that I have a layer.yaml file and if there's no hooks directory fail to push the charm. This would prevent sending up the unbuilt version of the code up to the charmstore.

[kwmonroe]

I ran charm proof on a layer and got the following:

$ charm proof
I: metadata name (giraph) must match directory name (layer-giraph) exactly for local deployment.
I: no hooks directory
I: missing recommended hook install
I: missing recommended hook start
I: missing recommended hook stop
I: File config.yaml not found.

Perhaps we should change the I: no hooks directory to an E, and require charm push to run proof first. That way, push would fail because proof would fail. Also, we shouldn't let people push charms that don't pass proof.