Refs #624: Remove "unset" option for contract type
Refs #624: Remove "unset" option for contract type

Branch: 624-remove-choice

caktus/django-timepiece,josesanch/django-timepiece,BocuStudio/django-timepiece,dannybrowne86/django-timepiece,dannybrowne86/django-timepiece,gaga3966/django-timepiece,arbitrahj/django-timepiece,BocuStudio/django-timepiece,arbitrahj/django-timepiece,dannybrowne86/django-timepiece,gaga3966/django-timepiece,josesanch/django-timepiece,arbitrahj/django-timepiece,caktus/django-timepiece,josesanch/django-timepiece,BocuStudio/django-timepiece,caktus/django-timepiece,gaga3966/django-timepiece