The previous method of using the forever monitor daemon with upstart
failed at being able to write to the pid-file upon reboot. This showed
up in Vagrant testing and I believe it has something to do with the fact
that we're creating the pidfile manually within the play.

I have prior experience with NodeJS+Upstart and it turns out that
forever isn't actually necessary at all. With `console log` and
`respawn` directives, and an unforked process, Upstart properly tracks
the PID (without a pidfile), respawns the process should it die, and
logs by default to `/var/log/upstart/rocketchat.log`

This changeset removes the following tasks and has the added benefit of
simplifying the play overall:

- Ensure Forever (NodeJS) is installed [Ubuntu 14]
- Check to see if the Rocket.Chat log file is present [Ubuntu 14]
- Ensure the Rocket.Chat log file is present [Ubuntu 14]
- Ensure the Rocket.Chat pid file is present [Ubuntu 14]

The former log-file path has been replaced with a symlink pointing to
the new logfile path.

This fixes #11