add support for rsyslog v2 clients

add support for old clients using rsyslog v2. Like RedHat 5.4 and earlier or Suse 10.


It replace https://github.com/ghoneycutt/puppet-module-rsyslog/pull/44 where GH said:
instead of two templates for the same file, there should be conditional logic within the template.
Also, could you do a validate_re() on $rsyslog_conf_version to ensure it is '2' or '3'.
Oh yea, would also add a note about this to the Compatibility section of the README.

These line by line matches are pretty confusing to ensure that we have everything. What do you think about using fixtures and comparing against the whole file?