Begin of the insertion### Steps to reproduceEnd of the insertion Begin of the deletion End of the deletion

Begin of the insertion1. Login as a user

2. Go to a work package and add some dates

3. Try to delete the start and end date


### What is the buggy behavior?

The dates are not removed at all

### What is the expected behavior?

Deleting the dates should remove both of them

**Operating System**

* [ ] Windows
* [ ] Mac OS X
* [x] Mobile iOS
* [x] Mobile Android
* [ ] Linux (please specify distro)
* [ ] Chrome OS
* [ ] Other (please specify)End of the insertion