Delete DownloadSchedule options in chutney
After legacy/trac#23354 (moved) is merged, we will need to ignore the download schedule warnings in chutney. Perhaps this is a good time to add the InitialDelay equivalents, if that doesn't also result in a warning,
Once 0.2.5 is obsolete, we will not need any items in the schedule past the first item. So we should delete those, too.