donedate doesn't get set when adding completed torrents

[terrorobe]

When adding torrent files where all data is already locally available, transmission will not set donedate, resulting it to stay at 0. This seems to be caused by torrentRecheckCompleteness not considering this control flow [1]

transmission-remote will ignore these values [2] but projects down the line (e.g. transmissionrpc & flexget) rely on the dates being correct or at least have a good definition of "undefined" instead of 0.

[1] https://trac.transmissionbt.com/browser/trunk/libtransmission/torrent.c#L2171 [2] https://trac.transmissionbt.com/browser/trunk/daemon/remote.c#L994