Rework how we setup logging for Crowbar

There are two main changes:

  - instead of putting stdout/stderr in production.log, we put them in
    production.out.

  - we really use production.log to log things, instead of using syslog
    which loses the formatting and spams /var/log/messages.

The rationale for using syslog was "distributed setups", but since we
put the logs of chef-client runs in /opt/dell/crowbar_framework anyway,
I don't think this rationale stands.
Move production.log to /var/log/crowbar

We create the directory in the chef recipe, to be sure it's there (note
that it's using 0750 permissions to avoid leaking sensitive data).
Also move chef-client runs to /var/log/crowbar

They now live in /var/log/crowbar/chef-client.
Cleanup recipe code with a logdir variable
Merge pull request #648 from vuntz/rework-logging

https://github.com/crowbar/barclamp-crowbar/pull/648

Merged by devtool for VictorLowther