add support for rsyslog v2 clients

adds support for rsyslog v2.x clients like RHEL 5.4 and Suse 10.
It can choose the used version based on the installed rsyslog package. Alternatively it can be set via hiera.

This replaces https://github.com/ghoneycutt/puppet-module-rsyslog/pull/45

This only works on systems with rpm. Could you use `rsyslogd -v` to get this information.