The entry can be removed manually from the local file. Starting in Authentication Services 4.1 group policy extension the local entries can be replaced via group policy.
In the group policy object, by default the mode is merge,to change it to replace do the following:
1 - Right click on the users.allow/users.deny option,
2 - Select "Remove local configuration", the mode will change to replace. When in "replace" mode, local changes will be ignored.