Edit flavor access does not update removed access

[Santiago Baldassin]

Steps to reproduce:
1. In the Flavors section within Admin, edit any of the available flavors
2. Add an access to the flavor and save the changes
3. Edit again. Remove the access added in step 2 and add a new access and save the changes
4. Once again edit the same flavor, access added in step 2 should not be part of the flavor access since it was removed in step 3 but it is actually showing up as one of the flavor accesses

This is happening with the admin access which is added by default by nova. The problem is that if the admin access can't be removed from the flavor then the remove option should not be available for that access or the workflow information should warn the user about how the admin access works