Fix escape <%PRI%>

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>
Fix "if-then" syntax for rsyslog

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>
Merge pull request #351 from bogdando/fix_syslog

Fix syslog: 
* uninitialized constant Puppet::Parser::TemplateWrapper::PRI;
* small refactoring if/else syntax for rsyslog.