Add an option to clear priorities on the model attributes in catalog
Allow changing the parent in verified devices
Simplify localboot.txt
rfactor preboot_view and show a message when preboot is missing.
get_current_deployment never rises, but can return None
Just return 404 when no preboot file found.
Fix menu in the pricing groups
Fix pricing tests
Merge github.com:allegro/ralph
Merge pull request #424 from deshipu/master

clear priorities in catalog, return 404 instead of localboot, fix menus in pricing groups, fix pricing tests