LDAP users permission not mapped correctly if "Save Grav User" is disabled

[aasampaio]

Hi!

I've noticed that LDAP users with permissions other than "super-user" don't get their permission mapped correctly if the "Save Grav user" option is disabled.
For instance, a user with "login", "cache" and "pages" permissions only has their permissions correctly applied if the "Save Grav user" option is on. Otherwise they will not have access to the Pages menu item and won't be able to edit.