Remove Serrano version check from exporter collection model
Remove code that handled exports on really old Serrano versions

Cookies have been around longer than the minimum version of Serrano that Cilantro supports so we do not need to deal with the possibility of a cookie-less export reality any longer. The future is now and it has cookies.
Merge pull request #447 from cbmi/issue-385

Remove code that handled exports for cookie-less Serrano versions