• Add staging support.
• Handle scl.conf like syslog-ng.conf (with scl.conf.dist).
• Always install syslog-ng.conf.sample/dist, since they are example files.
• Use mkdir -p in pkg-plist to fix warning during reinstallations/upgrades.
• Sort pkg-plist.
• General cleanup.

(same as r330086)

Approved by: maintainer