Configure proxy with syslog by default
Smart proxy already have new SYSLOG setting which logs via syslog socket instead of a file. The only limitation is this uses Ruby 2.0+ class (http://ruby-doc.org/stdlib-2.0.0/libdoc/syslog/rdoc/Syslog/Logger.html).
We should do this by default on systems with Ruby 2.0+. With that change, we should change our logrotation scripts and syslog configuration to send into separate file (on non-systemd systems).
To avoid complexity in the installer, we can maybe wait until all supported platforms are Ruby 2.0+ or even better - systemd only.