Show only local roles when inherit=False

[tschorr]

When using api.group.get_roles with inherit=False, inherited roles from group memberships are shown along with local roles from adapters. This is inconsistent with what is displayed in the ZMI's manage_listLocalRoles and @@sharing. E.g. if you grant a local role to AuthenticatedUsers it is returned by get_roles for all other groups.

Suggestion: change behavior of get_roles when called with inherit=False to return only local roles for the requested group to make it consistent with ZMI and sharing tab.

Alternatively there could be an additional parameter/flag to make get_roles return only local roles.