Do not retry sending out posts on SSL errors.  See #4728

This pull request stops Diaspora from retrying bad SSL cert send jobs pointlessly.  It should clean up the podmin job queues a bit, I think joindiaspora.com's queue is mostly these useless http_multi jobs.  I'm planning on merging it once Travis gives the green light, then pulling it into joindiaspora to see how it affects the memory use/worker bloat issue.