Fix edit history dialog crash when event has non existent related entity
requested to merge budalokko/ktimetracker:ktimetracker-424993-opening-edit-history-dialog-crash-1 into master
Replaced qFatal() by qCWarning().
Project mantainer Alexander said "The code should be changed to ignore such errors" in the issue so this is what I tried.
Faulty event does not appear on the list then.