file that was already completely downloaded caused an error, while it
doesn't if you don't use --fail! I added test case 194 to verify the fix.
Grrr. CURLOPT_FAILONERROR is now added to the list stuff to remove in
libcurl v8 due to all the kludges needed to support it.

Open "debugit" in binary mode ("rb").

individual transfers

  app to retrieve the errno variable after a (connect) failure. It will make
  sense to provide this for more failures in a more generic way, but let's
  start like this.