Version is 4.14.17

Defining categories and then assigning new colors to those categories do not survive from session to session in a calendar that is synchronized with Google Calendar.

Reproducible: Always

Steps to Reproduce:
1. set up a calendar synchronized with Google Calendar
2. Add one or more categories.
3. Set colors for those categories that are not the default colors
4. add events that have categories
5. Log out from KDE.
6. Log back in and let korganizer reconnect to Google Calendar.
7. open korganizer
8. observe colors of events

Actual Results:  
Colors that were defined for categories return to default colors and events with those categories display with the default colors.

Expected Results:  
Colors for categories should be retained and the events with those categories should display with those colors.