Clean-up files use

- file_hack was a hack used in Essex and now outdated.
- nothing is using nova-novncproxy.init

This patch aims to delete files/* and file_hack.pp which is now
useless.

Change-Id: I94b40e34fd61d778c7450d149f49e28612c58d31
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>