[syslog-ng] RHEL 6 / CentOS 6 packages

[Peter Eckel]

Hi Peter, 

> There were many requests for RHEL 6 / CentOS 6 support. The last version compiling on these ancient platforms was syslog-ng 3.9. Bazsi provided a fix: https://github.com/balabit/syslog-ng/pull/1837 which I applied to the syslog-ng 3.13 branch.

IMHO these versions are by no means "ancient". They are fully supported versions, and in my experience there are still more EL6 instances running in production than EL7, which may or may not be correlated to the fact that many admins shirk away from systemd. 

Many thanks to Baszi for the patch!

Best regards, 

  Peter.