#476 and #489 Ensure that a license index is recreated only if needed
#476 and #489 Ensure that a license index is recreated only if needed

 * #476 introduced a regression where a license index cache was
   rebuilt if the cache needed even if a license scan was not requested
   This restore the proper behavior. And will be further updated with
   #489
 
Signed-off-by: Philippe Ombredanne <ca95c4a6a4931f366cbdaf5878c5016609417d37@nexb.com>
michaelrup/scancode-toolkit,yasharmaster/scancode-toolkit,yashdsaraf/scancode-toolkit,yasharmaster/scancode-toolkit,yashdsaraf/scancode-toolkit,yashdsaraf/scancode-toolkit,yasharmaster/scancode-toolkit,marcreyesph/scancode-toolkit,michaelrup/scancode-toolkit,yashdsaraf/scancode-toolkit,michaelrup/scancode-toolkit,michaelrup/scancode-toolkit,yashdsaraf/scancode-toolkit,michaelrup/scancode-toolkit,yasharmaster/scancode-toolkit,marcreyesph/scancode-toolkit,yashdsaraf/scancode-toolkit,yashdsaraf/scancode-toolkit,michaelrup/scancode-toolkit,yasharmaster/scancode-toolkit,yasharmaster/scancode-toolkit,michaelrup/scancode-toolkit,yashdsaraf/scancode-toolkit,marcreyesph/scancode-toolkit,marcreyesph/scancode-toolkit,yasharmaster/scancode-toolkit,michaelrup/scancode-toolkit,yasharmaster/scancode-toolkit,yasharmaster/scancode-toolkit,yasharmaster/scancode-toolkit,marcreyesph/scancode-toolkit,michaelrup/scancode-toolkit,michaelrup/scancode-toolkit,michaelrup/scancode-toolkit,marcreyesph/scancode-toolkit,marcreyesph/scancode-toolkit,michaelrup/scancode-toolkit,yashdsaraf/scancode-toolkit,marcreyesph/scancode-toolkit,yashdsaraf/scancode-toolkit,marcreyesph/scancode-toolkit,marcreyesph/scancode-toolkit,marcreyesph/scancode-toolkit,yasharmaster/scancode-toolkit,yashdsaraf/scancode-toolkit,yasharmaster/scancode-toolkit,marcreyesph/scancode-toolkit,yashdsaraf/scancode-toolkit