Remove old database-relation-changed.
Upstart fixes.
* Replaced existing upstart conf with simpler one from charm review.
* Updated upstart to set ubuntu as the user.
* Updated hooks to set ubuntu as the owner of ghost files (/var/www/ghost, /var/log/ghost.log)
* Updated start hook to use upstart service with restart for idempotent start.
Merge pull request #19 from jaycee/bits-and-bobs

Adds Upstart to keep Ghost running and hook fixes