Cron model does not clean Minute, Hour, Day and Weekday when interval type changes
Scenario to reproduce:
- Create a new cron record with interval_type = months and interval_number = 1
- Also set any of the Minute, Hour, Day or Weekday fields. For example, set Hour = 14
- Change again the interval_type = hours and interval_number = 12
- Save
Given that Minute, Hour, Day and Weekday fields are not cleaned when the user changes the interval_type to "hours", when next call is computed:
https://hg.tryton.org/trytond/file/tip/trytond/ir/cron.py#l96
It will take those (Minute, Hour, Day, Weekday) fields into account so the cron process, instead of executing once every 12 hours it will run more frequently.