Handle timeouts in the Haskell backend

.. and other http errors. Just retry.

backend: HttpExceptionRequest Request {
  host                 = "www.reddit.com"
  port                 = 443
  secure               = True
  requestHeaders       = [("User-Agent","haskell wreq-0.5.1.0")]
  path                 = "/r/zerocarb/top/.json"
  queryString          = "?sort=top&t=week&limit=3"
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
}
 (ConnectionFailure Network.Socket.getAddrInfo: does not exist (nodename nor servname provided, or not known))