[FIX] event: added missing description on event.event model, leading to event model having Email Thread has description due to inheritance.
[Fix] hr_timesheet: When changing the date in timesheet activities gives alert, but alert is not translatable.
Merge pull request #2789 from erwin-bas-solutions/translation-timesheet-alert

[Fix] hr_timesheet: Make alert translatable
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64