General improvements

Update init.pp to inherit params.pp instead of including it. This makes sure
that params.pp is always defined before needed. Also see [1] for more info.

private.key permission update from 0600 to 0400 …
private.key file does not need to have write permission. Updated to use 0400.

[1] https://groups.google.com/forum/#!topic/puppet-users/A4DK0eXLJnc