R_s2, PT hostname, and syslog-ng version & certs

* upgraded to remote_syslog2, which solves a [known issue](https://github.com/papertrail/remote_syslog#sending-messages-securely) with the gem's support for TLS
* Papertrail hostname can now be configured for `logs.papertrailapp.com` or `logs2.papertrailapp.com`
* syslog-ng has been upgraded to 3.3.5-r1 (taken from [this](https://github.com/engineyard/ey-cloud-recipes/pull/166) PR)
* now uses a new certificate bundle that's compatible with `logs` & `logs2`