Description of problem:

in migration waves - after editing a migration wave and applying wrong dates then correcting the dates does not remove the error message "
Start date must be before end date"

Version-Release number of selected component (if applicable): 

How reproducible: always

Steps to Reproduce:
1.Navigate to migration waves tab
2.Edit a migration wave
3.Apply Start date after the end date - error message should be shown

4.apply correct end date (after the start date)

5. the message still present 

Actual results:

the error message is still shown even after correcting the end date

Expected results:

the error message should be gone when correcting the end date

Additional info: