syslog-ng: Update from 3.5.6 to 3.6.1

Also update the NixOS module, syslog-ng now automatically listens to
the systemd journal, so we don't have to set up syslog.socket.

(cherry picked from commit e2ada42623f26d51cf7d1253ac0700297e1a9b83)
New pkg: syslog-ng-incubator

A collection of tools and modules for syslog-ng

(cherry picked from commit 233825760c94e3e1a44a76cf0b93578757a1e10a)
Up syslog-ng-incubator to work with syslog-ng 3.6

Also disable riemann extension, since it is now part of 3.6.

(cherry picked from commit 3b6953abdff2ead15b48f7f5e7df0497e90ab723)
New pkg: riemann-c-client version 1.1.1

A C client library for the Riemann monitoring system

(cherry picked from commit 0ee69ef5293aa1bfdc0fcba4857f6f29392047db)
riemann-c-client: Update from 1.2.0 to 1.2.1

(cherry picked from commit 5c9157b3294d7c6cda6c32152b254650daa116cf)
Fix build errors caused by rename.nix
Fix cherry-pick error