Make `submit()` return its errors
Make `submit()` return its errors

* Logging of the errors is now done by the caller.
* This change makes it possible for the caller to decide how to handle
  errors. Ie. retry etc.

akundu/statsdaemon,alexclear/statsdaemon,bitly/statsdaemon,eliothedeman/statsdaemon,mikechris/statsdaemon,vimeo/statsdaemon,AudienceScience/statsdaemon,Zariel/statsdaemon,nejec/statsdaemon,bitly/statsdaemon,ploxiln/statsdaemon,shawnbutts/statsdaemon,raintank/statsdaemon,JamesCohen-awin/statsdaemon,wojtekzw/statsdaemon,raintank/statsdaemon,deepglint/statsdaemon,jmptrader/statsdaemon,wojtekzw/statsdaemon,vimeo/statsdaemon,raintank/statsdaemon,jmptrader/statsdaemon,mikechris/statsdaemon,aeppert/statsdaemon,ctdk/statsdaemon,gitinsky/statsdaemon,Zariel/statsdaemon,mikechris/statsdaemon,AudienceScience/statsdaemon,wojtekzw/statsdaemon,Huangyan9188/statsdaemon,ploxiln/statsdaemon,vimeo/statsdaemon,JamesCohen-awin/statsdaemon,akundu/statsdaemon,aeppert/statsdaemon