- Made the pingpong timeout code properly deal with the response timeout AND

- Made the pingpong timeout code properly deal with the response timeout AND
  the global timeout if set. Also, as was reported in the bug report #2956437
  by Ryan Chan, the time stamp to use as basis for the per command timeout was
  not set properly in the DONE phase for FTP (and not for SMTP) so I fixed
  that just now. This was a regression compared to 7.19.7 due to the
  conversion of FTP code over to the generic pingpong concepts.

  http://curl.haxx.se/bug/view.cgi?id=2956437