Modify `deploy` to notify users when it starts deleting files

[jamesyc]

Modify deploy to notify users when it starts deleting files

If you do a deploy and cancel it... the first step of deploy is to delete the old deployed files. So you cannot run activate after a cancelled deploy, you must do a new deploy.

[jamesyc]

Add a line saying "Deleting old deployed files..." so users don't try to run activate after cancelling a deploy run; they need a fresh deploy.