Update papertrail recipe to work on both stable-v2 and stable-v4 stacks.

[yemartin]

I just checked the recipe an a v2 and a v4 environments and they both worked, but you may want to make sure too.

Thanks to Christopher Rigor for the stack version detection code.
Check zendesk Request #70359 for additional background information.

[dennisjbell]

Cannot rely on chef version to determine if using Gentoo 2009 (stable-v2) vs Gentoo-12.11 (stable-v4), as there is a stable-v3 stack that uses chef 10, but still uses gentoo 2009 packages. A new way for determining stack type is being developed, and I will update this ticket when its ready for consumption.

[yemartin]

Any ETA on the new way for determining stack type? I am currently upgrading our main apps to v4 and I am hitting the same stack version issue on other recipes (redis in particular).

[andrewjwu]

Tried upgrading from stable-v2 to v4 and the recipe failed while attempting to install syslog-ng. This commit fixed it, thanks!

package 'app-admin/syslog-ng' do
  version PAPERTRAIL_CONFIG[:syslog_ng_version]
  action :install
end