- Based on the Debian bug report #474224 that complained about the FTP error

  message when libcurl doesn't get a 220 back immediately on connect, I now
  changed it to be more specific on what the problem is. Also worth noticing:
  while the bug report contains an example where the response is:

    421 There are too many connected users, please try again later

  we cannot assume that the error message will always be this readable nor
  that it fits within a particular boundary etc.